Article Cite This: J. Org. Chem. 2018, 83, 2714−2724
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Organocatalytic Asymmetric Sequential 1,6-Addition/Acetalization of 1‑Oxotetralin-2-carbaldehyde to ortho-HydroxyphenylSubstituted para-Quinone Methides for Synthesis of Spiro-3,4dihydrocoumarins Zhi-Pei Zhang, Li Chen, Xin Li,* and Jin-Pei Cheng State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China S Supporting Information *
ABSTRACT: A chiral squaramide catalyzed approach constructing spiro-3,4-dihydrocoumarin motif by the enantioselective 1,6addition/acetalization reactions of 1-oxotetralin-2-carbaldehydes and ortho-hydroxyphenyl-substituted para-quinone methides followed by an oxidation was developed. The reactions proceeded smoothly with a wide range of p-QMs and 1-oxotetralin-2carbaldehydes to generate corresponding products in high yields with excellent diastereoselectivities (>19:1 dr) and enantioselectivities (up to 99% ee).
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INTRODUCTION As one of very important structural motifs, chiral dihydrocoumarin skeleton exists in a number of natural products and pharmaceuticals. Compounds incorporating a chiral dihydrocoumarin core structure have been found to exhibit a wide spectrum of biological activity, such as antioxidation, antitumor, and anti-inflammatory properties (Figure 1).1 Besides, these specific compounds can serve as momentous synthesis intermediates in organic chemistry.2 Because of the aforementioned significance of chiral dihydrocoumarin type compounds, the synthesis of corresponding chiral dihydrocoumarin derivatives had attracted great attention. As a result, a large number of researches, including [4 + 2] cycloaddition of ortho-quinone methides (QMs), Michael addition of 2-(2nitrovinyl)phenol with different nucleophilic reagents, kinetic resolution, and some other practical methods have been developed as practical strategies for the asymmetric synthesis of dihydrocoumarin derivatives in recent years.3 Despite these advances, the strategies for the preparation of chiral spirodihydrocoumarins were limited. In 2011, Hong reported the asymmetric domino Michael/acetalization reactions of 2hydroxynitrostyrenes and 1-oxotetralin-2-carbaldehydes with a chiral bifunctional thiourea catalyst, followed by oxidation providing the 1′,3-spiro-2′-oxocyclohexan-3,4-dihydrocoumarins (Scheme 1a).4 In 2012, Ramachary synthesized spirodihydrocoumarins through sequential Michael-lactonization reac© 2018 American Chemical Society
tions of 2-(2-nitrovinyl)phenols with alkyl cyclopentanone-2carboxylates catalyzed by a chiral thiourea followed by oxidation (Scheme 1a).5 Therefore, the development of efficient approaches to construct spirodihydrocoumarin type molecules in an enantioselective manner is still highly desirable for pharmaceutical assay and other fields. Because of the zwitterionic resonance structure of a cyclohexadiene moiety in para-conjugation with a carbonyl group that enhances the electrophilic character at the δposition, para-QMs are practically reactive intermediates for organic synthesis.6 As a pioneer of the work, Fan reported the first example of asymmetric organocatalytic 1,6-conjugate addition of p-QMs with diphenyl malonates.7 Soon after, Jørgensen developed an asymmetric α-alkylation of aldehydes by 1,6-conjugated addition of enamines to p-QMs.8 Over the next several years, the investigation of the reactions of p-QMs has become one of the most prevailing topics in the field of organic synthesis and great advances have been achieved. As a result, extensive studies have been focused on the 1,6-conjugate addition reactions or cycloaddition reactions of p-QMs.9,10 However, among the most aforementioned progress, p-QMs were acted as simple electrophiles, and no examples of the involvement of p-QMs in domino reactions were reported. In Received: December 17, 2017 Published: February 6, 2018 2714
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry
Figure 1. Examples of dihydrocoumarin type natural products and bioactive molecules.
89% yield and >19:1 diastereoselectivity and 99% ee (Table 1, entry 2). We also tested other bifunctional catalysts (C−F), and a no better result than B was found (Table 1, entries 3−6). Next, we studied the influence of different solvent in this reaction. Product 3aa was obtained with low yield and stereoselectivity in CH2Cl2 (Table 1, entry 7). Also, when toluene or benzotrifluoride was used as the solvent, the yield and stereoselectivity of product 3aa were all decreased (Table 1, entries 8 and 9). Moreover, ether type solvent, such as diethyl ether and tetrahydrofuran, could reduce reactivity seriously (Table 1, entries 10 and 11). Adding 4 Å molecular sieves to the reaction system seems to have no influence on the outcome (Table 1, entry 12). Lowing the catalyst loading can lead to a decrease in yield (Table 1, entry 13). With the optimal reaction conditions in hand, the substrate scopes of p-QMs and 1-oxotetralin-2-carbaldehydes were investigated. First, we chose 2a to test the substituent effect of the p-QMs. As shown in Table 2, the p-QMs with either electron-donating substituents or electron-withdrawing substituents on the para-position of the phenyl ring were quite amenable to the studied 1,6-addition/acetalization process and offered the corresponding products 3aa−3fa with very good yields (71−99%), excellent diastereoselectivities (>19:1), and enantioselectivities (99% ee). Furthermore, there was no obvious effect on the results when substituent groups were in the 4, 5, and 6 positions of the aryl ring of p-QMs (3fa−3ha). Next we tested the substrate scopes of the 1-oxotetralin-2carbaldehydes. As shown in Table 3, a number of 1-oxotetralin2-carbaldehydes, in which substituent R2 was either electronwithdrawing or electron-donating group on different position of the aryl ring, could be smoothly converted to the corresponding products in good yields, excellent enantioselectivities, and moderate to excellent diastereoselectivities (3ab−3ag, 75%− 98% yield, 98%−99% ee, and 5:1 ∼ >19:1 dr). Moreover, for 1benzosuberone-2-carbaldehyde 2h and 1-oxohydrindene-2carbaldehyde 2i, the corresponding products 3ah and 3ai were obtained with excellent results under the optimal conditions. Furthermore, substrate 2j that a methyl was on the para-position of the carbonyl could also react smoothly with 1a affording product 3aj with good yield and excellent enantioselectivity (94% yield, 1.5:1 dr, and 99%/99% ee). In addition, when 2-oxocyclohexane-1-carbaldehyde (2k) was used as the substrate, the 1,6-addition/acetalization strategy that also worked well gave product 3ak in 84% yield, >19:1 dr, and 99% ee. The absolute configuration of 3af, 3ah, and 3ak were determined by X-ray crystallographic analysis.16
2016, Enders described an asymmetric organocatalytic domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenylsubstituted p-QMs and isatin-derived enoates (Scheme 1b).11 In 2017, Jiang reported the AgTFA/BiNPO4H cocatalyzed 6endo-dig oxo-cyclization/[4 + 2] cycloaddition cascade reactions of β-alkynyl ketones and ortho-hydroxyphenyl-substituted pQMs for the synthesis of spiro[chromane-2,1′-isochromene] derivatives.12a Next, Jiang applied the same substrates realize the synthesis of tetracyclicbenzo[c]xanthenes through AgTFA/ Sc(OTf)3 cocatalyzed benzannulation/1,6-addition/cyclization sequences (Scheme 1c).12b Recently, Zhao reported the divergent cascade reactions of activated isocyanides with para-quinone methide aryl esters producing skeletally diverse tricyclic ketals and triarylmethanes under Ag (or Cu) catalysis (Scheme 1d).13 In 2017, Fan reported chiral amine-phosphines catalyzed intramolecular vinylogous Rauhut-Currier reaction of p-QMs, producing dihydrocoumarin derivatives (Scheme 1e).14 Very recently, this group reported the enantioselective reaction of azlactones and p-QMs by using a chiral phosphoric acid catalyst to synthesize functionalized chiral dihydrocoumarin derivatives (Scheme 1f).15a Despite the above impressive achievements, the development of new strategies for the enantioselective domino reactions of p-QMs is still a challenging and meaningful task. So far, p-QMs have not been used to construct important spirodihydrocoumarin skeleton yet. We envisioned that an organocatalytic 1,6addition/acetalization of ortho-hydroxyphenyl-substituted pQMs and 1-oxotetralin-2-carbaldehyde followed by oxidation could be an effective approach to the synthesis of chiral spirodihydrocoumarin derivatives (Scheme 1g). Herein, we reported a chiral squaramide catalyzed enantioselective 1,6addition/acetalization reactions of 1-oxotetralin-2-carbaldehydes and ortho-hydroxyphenyl-substituted para-quinone methides followed by an oxidation to produce spiro-3,4dihydrocoumarin motif.
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RESULTS AND DISCUSSION To probe the feasibility of the envisaged strategy, we select pQM 1a and 1-oxotetralin-2-carbaldehyde 2a as model substrates to start our research. The model reaction was initially performed in CHCl3 at room temperature, and the desired product 3aa was obtained in 37% yield, >19:1 diastereoselectivity, and 80% ee under bifunctional thiourea catalyst A (Table 1, entry 1). When bifunctional squaramide catalyst B was used, improvement of the activity and the stereoselectivity were observed, in which 3aa was gained with 2715
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry Scheme 1. Strategies for 1,6-Addition/Acetalization of ortho-Hydroxyphenyl-Substituted p-QMs
To probe the efficiency of the asymmetric 1,6-addition/ acetalization strategy, a gram-scale reaction of 1a and 2a was
investigated under the optimal reaction conditions. As a result, the intermediate 3a′ was obtained in 91% yield and 1.2:1 dr. 2716
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry Table 1. Optimization of the Reaction Conditionsa
entry
cat
solvent
time (h)b
yield (%)c
drd
ee (%)e
1 2 3 4 5 6 7 8 9 10 11 12f 13g
A B C D E F B B B B B B B
CHCl3 CHCl3 CHCl3 CHCl3 CHCl3 CHCl3 CH2Cl2 PhCH3 PhCF3 Et2O THF CHCl3 CHCl3
24 12 24 24 24 24 12 12 12 24 24 12 15
37 89 60 39 54 56 82 77 77 23 19:1 >19:1 >19:1 >19:1 >19:1 >19:1 13:1 >19:1 3:1 >19:1 Ndh >19:1 >19:1
80 99 94 75 92 84 98 99 98 98 Ndh 99 98
a The reactions were carried out with 1a (0.2 mmol), 2a (0.3 mmol), and 10 mol % catalyst in 2.0 mL of solvent at rt. bReaction time for 1,6addition. cYield of isolated products by two steps. dDetermined by 1H NMR analysis. eDetermined by HPLC analysis. f80 mg of 4 Å MS was added as additive. g5 mol % catalyst was used. DMP = Dess-Martin periodinane. hNot determined.
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CONCLUSIONS In summary, we have developed a highly enantioselective 1,6addition/acetalization reactions of 1-oxotetralin-2-carbaldehydes and ortho-hydroxyphenyl-substituted p-QMs by using bifunctional squaramide catalyst activation followed by an oxidation process. This strategy provides a novel and highly efficient method for the synthesis of functionalized spiro-3,4dihydrocoumarin derivatives in high yields with excellent diastereoselectivities and enantioselectivities. A range of functional groups were tolerated under the mild reaction conditions.
Then we chose 2.4 mmol of 3a′ to proceed to the next oxidation step. To our delight, the desired product 3aa was obtained in 92% yield, >19:1 dr, and 99% ee (Scheme 2). The synthetic applicability of this 1,6-addition/acetalization protocol was also investigated. As shown in Scheme 3, acylation with acetyl chloride in the presence of triethyl amine, 3a′ was transformed into stable product 4a′ in 97% yield with 1.2:1 dr and 99%/98% ee. In addition, 3a′ could also be dehydroxylated by treatment with triethylsilane and boron trifluoride etherate using dichloromethane as solvent, affording 5a′ with 60% yield and excellent stereoselectivity (>19:1 dr, 99% ee) (Scheme 3). When 3aa was treated with a mixture of Tf2O and TfOH in toluene for 12 h under Ar atmosphere, we successfully realized the detert-butylation of dihydrocoumarin and racemic 4aa was obtained in 81% yield with >19:1 dr (Scheme 3). The high temperature may be the reason for the racemization of the product.
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EXPERIMENTAL SECTION
General Information. Commercial reagents were used as received, unless otherwise stated. 1H and 13C NMR were recorded on 400 MHz spectrometer. Chemical shifts are reported in ppm from tetramethylsilane with the solvent resonance as the internal standard. The following abbreviations were used to designate chemical shift mutiplicities: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet. All first-order splitting patterns were assigned on the basis of 2717
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry Table 2. Substrate Scope of the p-QMsa
a The reactions were carried out with 1 (0.2 mmol), 2a (0.3 mmol), 10 mol % B in 2.0 mL of CHCl3 at rt for 12 h and another 1 h for oxidation in CH2Cl2 with DMP. Yield of isolated products after two steps. The dr values were determined by 1H NMR analysis. The ee values were determined by HPLC analysis.
5-Methoxy-1-oxo-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2d). Yellow solid, 1.61 g; 40% yield; mp 65−67 °C. 1H NMR (400 MHz, CDCl3) δ 14.569 (d, J = 6.7 Hz, 1H), 8.192 (d, J = 4.4 Hz, 1H), 7.590 (d, J = 7.8 Hz, 1H), 7.289 (t, J = 8.0 Hz, 1H), 7.013 (d, J = 8.2 Hz, 1H), 3.851 (s, 3H), 2.872 (t, J = 7.2 Hz, 2H), 2.601−2.442 (m, 2H). 13C NMR (100 MHz, CDCl3) δ 182.6, 176.6, 156.3, 132.6, 130.3, 127.3, 118.3, 114.4, 108.6, 55.8, 22.3, 21.1. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C12H13O3 205.0859, found 205.0863. 7-Bromo-1-oxo-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2e). Yellow solid, 4.56 g; 90% yield; mp 45−47 °C. 1H NMR (400 MHz, CDCl3) δ 14.427 (s, 1H), 8.246 (s, 1H), 8.021 (d, J = 2.2 Hz, 1H), 7.506 (dd, J = 8.1, 2.2 Hz, 1H), 7.097 (d, J = 8.1 Hz, 1H), 2.918− 2.759 (m, 2H), 2.653−2.477 (m, 2H). 13C NMR (100 MHz, CDCl3) δ 180.3, 177.8, 140.1, 135.4, 133.1, 129.8, 129.0, 120.8, 108.5, 28.2, 22.5. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C11H10BrO2 252.9859, found 252.9862. 7-Methyl-1-oxo-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2f). Brown solid, 3.69 g; 98% yield; mp 29−31 °C. 1H NMR (400 MHz, CDCl3) δ 14.654 (d, J = 6.8 Hz, 1H), 8.174 (s, 1H), 7.766 (s, 1H), 7.245 (d, J = 8.3 Hz, 1H), 7.115 (d, J = 7.8 Hz, 1H), 2.835 (t, J = 7.1 Hz, 2H), 2.591−2.472 (m, 2H), 2.367 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 183.0, 176.3, 138.7, 136.8, 133.8, 131.4, 128.1, 126.6, 108.8, 28.4, 23.1, 21.1. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C12H13O2 189.0910, found 189.0912. 1-Oxo-7-phenyl-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2g). Brown solid, 4.15 g; 83% yield; mp 48−50 °C. 1H NMR (400 MHz, CDCl3) δ 14.653 (d, J = 6.6 Hz, 1H), 8.289−8.138 (m, 2H), 7.725−7.574 (m, 3H), 7.443 (t, J = 6.9 Hz, 2H), 7.400−7.320 (m, 1H), 7.297 (d, J = 7.9 Hz, 1H), 2.917 (t, J = 7.1 Hz, 2H), 2.594 (t, J = 7.1 Hz, 2H). 13C NMR (100 MHz, CDCl3) δ 182.4, 177.1, 140.5, 140.2, 140.1, 132.0, 131.4, 129.0, 128.7, 127.7, 127.1, 124.8, 108.8, 28.6, 22.9. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C17H15O2 251.1067, found 251.1069. 5-Oxo-6,7,8,9-tetrahydro-5H-benzo[7]annulene-6-carbaldehyde (2h). Brown liquid, 2.97 g; 79% yield. 1H NMR (400 MHz, CDCl3) δ
the appearance of the multiplet. Splitting patterns that could not be easily interpreted are designated as multiplet (m). Mass spectra were obtained using electrospray ionization (ESI) mass spectrometer. The enantiomeric excesses were determined by HPLC analysis, which employ a chiral stationary phase column specified in the individual experiment, by comparing the samples with the appropriate racemic mixtures. The ortho-hydroxyphenyl-substituted para-quinone methides (p-QMs) 1a−1h were prepared according to the reported literature procedures.11,17 The 1-oxotetralin-2-carbaldehyde 2a−2k were prepared according to the reported literature procedures.18 1-Oxo-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2a). Brown liquid, 8.03 g; 92% yield. 1H NMR (400 MHz, CDCl3) δ 14.623 (s, 1H), 8.209 (s, 1H), 7.955 (d, J = 7.7 Hz, 1H), 7.434 (dd, J = 8.4, 6.8 Hz, 1H), 7.330 (t, J = 7.6 Hz, 1H), 7.224 (d, J = 7.6 Hz, 1H), 2.885 (t, J = 7.2 Hz, 2H), 2.567 (t, J = 7.2 Hz, 2H). 13C NMR (100 MHz, CDCl3) δ 182.4, 177.0, 141.6, 132.9, 131.6, 128.2, 127.1, 126.4, 108.7, 28.9, 22.9. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C11H11O2 175.0754, found 175.0756. 7-Methoxy-1-oxo-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2b). Brown liquid, 3.61 g; 89% yield. 1H NMR (400 MHz, CDCl3) δ 14.581 (s, 1H), 8.104 (s, 1H), 7.443 (d, J = 2.8 Hz, 1H), 7.116 (d, J = 8.3 Hz, 1H), 6.984 (dd, J = 8.3, 2.8 Hz, 1H), 3.817 (s, 3H), 2.854−2.708 (m, 2H), 2.582−2.455 (m, 2H). 13C NMR (100 MHz, CDCl3) δ 183.2, 175.5, 158.6, 134.1, 132.5, 129.2, 120.2, 109.4, 108.8, 55.5, 27.9, 23.2. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C12H13O3 205.0859, found 205.0862. 6-Methoxy-1-oxo-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2c). Yellow solid, 3.50 g; 85% yield; mp 57−59 °C. 1H NMR (400 MHz, CDCl3) δ 14.676 (s, 1H), 7.936−7.858 (m, 2H), 6.808 (dd, J = 8.7, 2.6 Hz, 1H), 6.681 (d, J = 4.4 Hz, 1H), 3.816 (s, 3H), 2.867−2.759 (m, 2H), 2.506 (t, J = 7.2 Hz, 2H). 13C NMR (100 MHz, CDCl3) δ 184.5, 172.4, 163.4, 144.4, 128.7, 124.9, 113.0, 112.8, 108.1, 55.4, 29.3, 23.2. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C12H13O3 205.0859, found 205.0861. 2718
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry Table 3. Substrate Scope of the 1-Oxotetralin-2-carbaldehydesa
a
The reactions were carried out with 1a (0.2 mmol), 2 (0.3 mmol), and 10 mol % B in 2.0 mL of CHCl3 at rt for 12 h and another 1 h for oxidation in CH2Cl2 with DMP. Yield of isolated products after two steps. The dr values were determined by 1H NMR analysis. The ee values were determined by HPLC analysis. 14.929 (d, J = 7.1 Hz, 1H), 8.053 (d, J = 6.4 Hz, 1H), 7.619 (dd, J = 7.5, 1.5 Hz, 1H), 7.418 (td, J = 7.5, 1.6 Hz, 1H), 7.345 (td, J = 7.5, 1.3 Hz, 1H), 7.216 (dd, J = 7.5, 1.2 Hz, 1H), 2.706 (t, J = 6.9 Hz, 2H), 2.150−1.943 (m, 4H). 13C NMR (100 MHz, CDCl3) δ 192.2, 176.6, 140.2, 137.5, 131.7, 129.2, 127.6, 126.9, 112.4, 31.2, 31.2, 24.1. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C12H13O2 189.0910, found 189.0912. 1-Oxo-2,3-dihydro-1H-indene-2-carbaldehyde (2i). Yellow solid, 2.24 g; 70% yield; mp 98−100 °C. 1H NMR (400 MHz, DMSO-d6) δ 11.235 (s, 1H), 7.799 (s, 1H), 7.660 (d, J = 7.6 Hz, 1H), 7.621−7.524 (m, 2H), 7.399 (ddd, J = 8.2, 6.7, 1.7 Hz, 1H), 3.580 (d, J = 1.6 Hz, 2H). 13C NMR (100 MHz, DMSO-d6) δ 192.4, 152.0, 148.0, 139.4,
133.2, 127.2, 126.4, 122.5, 113.8, 28.4. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C10H9O2 161.0597, found 161.0598. 4-Methyl-1-oxo-1,2,3,4-tetrahydronaphthalene-2-carbaldehyde (2j). Brown liquid, 3.05 g; 81% yield. 1H NMR (400 MHz, CDCl3) δ 14.621 (s, 1H), 8.148 (s, 1H), 7.962 (dd, J = 7.7, 1.4 Hz, 1H), 7.459 (td, J = 7.5, 1.5 Hz, 1H), 7.318 (td, J = 7.6, 1.2 Hz, 1H), 7.286−7.226 (m, 1H), 3.033 (h, J = 6.6 Hz, 1H), 2.721 (dd, J = 14.5, 5.4 Hz, 1H), 2.320 (dd, J = 14.5, 6.3 Hz, 1H), 1.259 (d, J = 7.0 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 182.3, 176.8, 146.5, 133.2, 130.6, 126.9, 126.9, 126.4, 107.1, 32.8, 30.3, 20.6. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C12H13O2 189.0910, found 189.0911. 2-Oxocyclohexane-1-carbaldehyde (2k). Brown liquid, 1.31 g; 52% yield. 1H NMR (400 MHz, CDCl3) δ 14.414 (d, J = 3.2 Hz, 1H), 2719
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry
hexane = 1:19), 1.0 mL/min; major isomer, t1 = 7.51 min, t2 = 10.55 min; minor isomer, t1 = 9.16 min, t2 = 12.79 min; [α]25 D 190.4 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-6-fluoro-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ba). Light yellow solid, 89.1 mg; 89% yield; mp 198−200 °C. 1H NMR (400 MHz, CDCl3) δ 7.866 (dd, J = 8.1, 1.4 Hz, 1H), 7.535 (td, J = 7.5, 1.5 Hz, 1H), 7.349−7.261 (m, 2H), 7.177 (dd, J = 9.0, 4.6 Hz, 1H), 7.029 (s, 2H), 6.980−6.895 (m, 1H), 6.711 (dd, J = 8.3, 2.9 Hz, 1H), 5.248 (s, 1H), 4.281 (s, 1H), 3.122 (ddd, J = 17.3, 12.1, 4.7 Hz, 1H), 2.920 (dt, J = 17.8, 4.2 Hz, 1H), 2.772 (ddd, J = 14.3, 12.2, 5.2 Hz, 1H), 2.033−1.929 (m, 1H), 1.395 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.5, 168.6, 159.1(d, 1JC−F = 246.2 Hz), 153.7, 146.8, 142.8, 136.8, 134.4, 129.0 (d, 3JC−F = 8.1 Hz), 128.8, 128.7, 127.3, 126.0, 125.9, 124.4, 118.3 (d, 3JC−F = 8.1 Hz), 115.7 (d, 2JC−F = 23.4 Hz), 115.2 (d, 2 JC−F = 23.4 Hz), 47.2, 34.6, 30.3, 27.2, 24.4. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C32H33FO4Na 523.2261, found 523.2258. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol−hexane = 1:19), 1.0 mL/min; major isomer, t1 = 9.39 min, t2 = 12.36 min. [α]25 D 177.2 (c 1.0, CHCl3). (3S,4S)-6-chloro-4-(3,5-ditert-butyl-4-hydroxyphenyl)-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ca). White solid, 100.3 mg; 97% yield; mp 97−99 °C. 1H NMR (400 MHz, CDCl3) δ 7.876 (d, J = 7.8 Hz, 1H), 7.593−7.506 (m, 1H), 7.315 (t, J = 8.4 Hz, 2H), 7.248−7.126 (m, 2H), 6.996 (d, J = 12.6 Hz, 3H), 5.238 (d, J = 1.3 Hz, 1H), 4.253 (s, 1H), 3.120 (ddd, J = 17.4, 12.3, 4.7 Hz, 1H), 2.915 (d, J = 26.2 Hz, 1H), 2.772 (td, J = 13.3, 12.8, 5.1 Hz, 1H), 1.953 (d, J = 14.4 Hz, 1H), 1.396 (d, J = 1.4 Hz, 18H). 13C NMR (100 MHz, CDCl3) δ 193.4, 168.4, 153.7, 149.5, 142.8, 137.0, 134.4, 130.0, 129.6, 129.0, 129.0, 128.9, 128.8, 128.6, 127.4, 126.1, 124.3, 118.4, 56.8, 47.2, 34.6, 30.3, 27.2, 24.4. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C32H33ClO4Na 539.1965, found 539.1965. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol−hexane = 1:19), 1.0 mL/min; major isomer, t1 = 12.73 min, t2 = 14.79 min. [α]25 D 127.1 (c 1.0, CHCl3). (3S,4S)-6-bromo-4-(3,5-ditert-butyl-4-hydroxyphenyl)-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3da). Light yellow oil, 79.7 mg; 71% yield. 1H NMR (400 MHz, CDCl3) δ 7.873 (d, J = 7.9 Hz, 1H), 7.544 (t, J = 7.7 Hz, 1H), 7.408−7.272 (m, 3H), 7.110 (d, J = 13.7 Hz, 2H), 7.007 (s, 2H), 5.246 (d, J = 1.6 Hz, 1H), 4.256 (s, 1H), 3.118 (ddd, J = 17.4, 12.3, 4.6 Hz, 1H), 2.911 (d, J = 18.0 Hz, 1H), 2.766 (td, J = 13.3, 12.8, 5.1 Hz, 1H), 1.950 (d, J = 18.4 Hz, 1H), 1.397 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.4, 168.3, 153.7, 150.0, 142.8, 136.9, 134.4, 131.9, 131.4, 129.9, 129.0, 128.9, 128.8, 127.4, 126.5, 124.3, 118.8, 117.2, 56.8, 47.1, 34.6, 30.3, 27.2, 24.4. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C32H33BrO4Na 583.1460, found 583.1458. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol−hexane = 1:19),
Scheme 2. Gram-Scale Synthesis
8.637 (d, J = 2.7 Hz, 1H), 2.340 (dt, J = 10.9, 5.8 Hz, 4H), 1.683 (ddtt, J = 12.3, 8.5, 5.6, 3.2 Hz, 4H). 13C NMR (100 MHz, CDCl3) δ 187.9, 184.9, 109.0, 31.3, 23.2, 22.7, 21.4. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C7H11O2 127.0754, found 127.0753. General Procedure for the Asymmetric Synthesis of 3. To a stirred solution of p-QMs 1 (0.2 mmol) and 1-oxotetralin-2carbaldehyde 2 (0.3 mmol) in dry CHCl3 (2.0 mL) at room temperature were added catalyst B (0.02 mmol). The reactions were monitored by TLC. After 1 were consumed completely, the reaction solutions were concentrated in vacuo and the crude products were purified by flash chromatography eluting with petroleum ether/ethyl acetate 5:1) to afford the products 3′. Then, DMP (Dess-Martin periodinane) (1.5 equiv) were added to a solution of 3′ in 5 mL of CH2Cl2 and the reactions were monitored by TLC. After 3′ were consumed completely, the reaction solutions were concentrated in vacuo and the crude products were purified by flash chromatography eluting with petroleum ether/ethyl acetate 10:1) to afford the products 3. (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-3′,4′-dihydro-1′Hspiro[chromane-3,2′-naphthalene]-1′,2-dione (3aa). White solid, 85.9 mg; 89% yield; mp 218−220 °C. 1H NMR (400 MHz, CDCl3) δ 7.848 (d, J = 7.9 Hz, 1H), 7.592−7.464 (m, 1H), 7.363−7.181 (m, 4H), 7.036 (s, 2H), 6.977 (s, 2H), 5.197 (s, 1H), 4.327 (s, 1H), 3.157 (d, J = 13.9 Hz, 1H), 2.907 (d, J = 17.7 Hz, 1H), 2.775 (t, J = 13.9 Hz, 1H), 1.987 (d, J = 17.5 Hz, 1H), 1.382 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.7, 168.9, 153.5, 150.9, 142.8, 136.7, 134.2, 130.2, 129.4, 128.9, 128.8, 128.6, 127.2, 124.7, 124.4, 124.4, 117.0, 57.0, 47.2, 34.6, 30.3, 27.2, 24.5. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C32H34O4Na 505.2355, found 505.2352. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol−
Scheme 3. Transformation of the Product
2720
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry 1.0 mL/min; major isomer, t1 = 12.84 min, t2 = 14.89 min. [α]25 D 89.0 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-6-methyl-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ea). Light yellow solid, 98.3 mg; 99% yield; mp 110−112 °C. 1H NMR (400 MHz, CDCl3) δ 7.861 (d, J = 7.9 Hz, 1H), 7.520 (t, J = 7.6 Hz, 1H), 7.291 (d, J = 7.7 Hz, 2H), 7.068 (d, J = 14.4 Hz, 4H), 6.783 (s, 1H), 5.207 (s, 1H), 4.254 (s, 1H), 3.139 (ddd, J = 17.5, 12.3, 4.7 Hz, 1H), 2.895 (d, J = 18.1 Hz, 1H), 2.769 (td, J = 13.3, 5.0 Hz, 1H), 2.177 (s, 3H), 1.944 (dt, J = 14.4, 3.9 Hz, 1H), 1.395 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.8, 169.1, 153.4, 148.7, 142.8, 136.7, 134.2, 134.2, 130.2, 129.6, 129.5, 129.0, 128.9, 128.8, 127.2, 124.4, 123.9, 116.6, 57.1, 47.2, 34.6, 30.3, 27.2, 24.4, 20.9. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O4Na 519.2511, found 519.2510. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol−hexane = 1:19), 1.0 mL/min; major isomer, t1 = 28.61 min, t2 = 38.34 min. [α]25 D 126.8 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-6-methoxy-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3fa). Light yellow solid, 101.5 mg; 99% yield; mp 90−92 °C. 1H NMR (400 MHz, CDCl3) δ 7.863 (d, J = 8.6 Hz, 1H), 7.564−7.470 (m, 1H), 7.279 (t, J = 8.1 Hz, 2H), 7.138 (d, J = 8.9 Hz, 1H), 7.051 (s, 2H), 6.773 (dd, J = 8.9, 3.0 Hz, 1H), 6.509 (d, J = 2.9 Hz, 1H), 5.226 (s, 1H), 4.271 (s, 1H), 3.660 (s, 3H), 3.136 (ddd, J = 17.3, 12.2, 4.7 Hz, 1H), 2.972−2.840 (m, 1H), 2.840−2.698 (m, 1H), 2.045−1.909 (m, 1H), 1.392 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.7, 169.0, 156.1, 153.4, 144.7, 142.8, 136.6, 134.2, 130.1, 129.2, 128.9, 128.7, 127.2, 125.2, 124.4, 117.6, 113.8, 113.7, 56.9, 55.5, 47.4, 34.5, 30.3, 27.2, 24.4. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O5Na 535.2460, found 535.2458. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol− hexane = 1:19), 1.0 mL/min; major isomer, t1 = 13.21 min, t2 = 20.66 min. [α]25 D 90.4 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-7-methoxy-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ga). Light yellow solid, 96.4 mg; 94% yield; mp 105−107 °C. 1H NMR (400 MHz, CDCl3) δ 7.855 (d, J = 7.2 Hz, 1H), 7.558−7.471 (m, 1H), 7.271 (dd, J = 14.7, 6.5 Hz, 2H), 7.024 (s, 2H), 6.882 (d, J = 8.4 Hz, 1H), 6.764 (d, J = 2.5 Hz, 1H), 6.537 (dd, J = 8.4, 2.5 Hz, 1H), 5.199 (s, 1H), 4.271 (s, 1H), 3.775 (s, 3H), 3.147 (td, J = 12.5, 6.2 Hz, 1H), 2.950−2.846 (m, 1H), 2.814−2.702 (m, 1H), 1.964 (dt, J = 14.3, 3.9 Hz, 1H), 1.390 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.8, 169.0, 160.0, 153.3, 151.6, 142.8, 136.6, 134.2, 130.1, 129.9, 129.1, 128.9, 128.0, 127.2, 124.2, 116.4, 111.0, 102.2, 57.2, 55.5, 466, 34.5, 30.3, 27.2, 24.4. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O5Na 535.2460, found 535.2457. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol− hexane = 1:19), 1.0 mL/min; major isomer, t1 = 14.05 min, t2 = 19.19 min. [α]25 D 140.0 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-8-methoxy-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ha). White solid, 97.4 mg; 95% yield; mp 116−118 °C. 1H NMR (400 MHz, CDCl3) δ 7.969−7.805 (m, 1H), 7.565−7.466 (m, 1H), 7.343− 7.212 (m, 2H), 7.048 (s, 2H), 6.966−6.876 (m, 1H), 6.840 (d, J = 8.3 Hz, 1H), 6.578 (d, J = 9.1 Hz, 1H), 5.203 (s, 1H), 4.332 (s, 1H), 3.935 (s, 3H), 3.102 (ddd, J = 17.2, 12.0, 4.7 Hz, 1H), 2.961−2.846 (m, 1H), 2.838−2.715 (m, 1H), 2.097−1.966 (m, 1H), 1.387 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.5, 168.3, 153.4, 147.6, 142.8, 140.1, 136.6, 134.1, 130.2, 129.3, 128.9, 128.7, 127.1, 125.3, 124.6, 124.5, 120.0, 111.7, 56.6, 56.4, 47.3, 34.5, 30.3, 27.2, 24.5. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O5Na 535.2460, found 535.2460. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol−hexane = 1:19), 1.0 mL/min; major isomer, t1 = 10.40 min, t2 = 33.94 min. [α]25 D 176.7 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-7′-methoxy-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ab). Light yellow solid, 100.5 mg; 98% yield; mp 106−108 °C. 1H NMR (400 MHz, CDCl3) δ 7.308 (d, J = 2.9 Hz, 1H), 7.287−7.174 (m, 3H), 7.108 (dd, J = 8.5, 2.8 Hz, 1H), 7.045 (s, 2H), 7.020−6.953 (m, 2H), 5.206 (s, 1H), 4.326 (s, 1H), 3.743 (s, 3H), 3.074 (ddd, J = 16.9,
12.0, 4.6 Hz, 1H), 2.904−2.699 (m, 2H), 1.974 (dt, J = 14.2, 3.9 Hz, 1H), 1.388 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.7, 169.0, 158.7, 153.4, 150.8, 136.6, 135.3, 130.8, 130.1, 129.5, 128.9, 128.6, 124.7, 124.4, 124.4, 122.9, 116.8, 110.2, 56.9, 55.6, 47.2, 34.5, 30.3, 27.5, 23.7. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O5Na 535.2460, found 535.2459. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol−hexane = 1:9), 1.0 mL/min; major isomer, t1 = 16.43 min, t2 = 32.36 min; minor isomer, t1 = 19.05 min, t2 = 23.57 min. [α]25 D 209.8 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-6′-methoxy-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ac). White solid, 88.2 mg; 86% yield; mp 121−123 °C. 1H NMR (400 MHz, CDCl3) δ 7.822 (d, J = 8.8 Hz, 1H), 7.212 (q, J = 8.1, 7.1 Hz, 2H), 7.039 (s, 2H), 6.977 (d, J = 6.3 Hz, 2H), 6.797 (d, J = 8.7 Hz, 1H), 6.730 (s, 1H), 5.195 (s, 1H), 4.311 (s, 1H), 3.857 (s, 3H), 3.199−3.035 (m, 1H), 2.934−2.674 (m, 2H), 2.028−1.875 (m, 1H), 1.383 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 192.3, 169.2, 164.2, 153.4, 150.9, 145.3, 136.6, 131.2, 129.7, 128.8, 128.6, 124.6, 124.6, 124.4, 123.4, 116.8, 114.0, 112.5, 56.8, 55.6, 47.5, 34.5, 30.3, 27.4, 24.9. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O5Na 535.2460, found 535.2458. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol−hexane = 1:9), 1.0 mL/min; minor isomer, t1 = 11.91 min, t2 = 13.51 min. [α]25 D 192.5 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-5′-methoxy-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ad). White solid, 93.4 mg; 91% yield; mp 109−111 °C. 1H NMR (400 MHz, CDCl3) δ 7.421 (d, J = 7.8 Hz, 1H), 7.289−7.170 (m, 3H), 7.055 (d, J = 10.7 Hz, 3H), 6.962 (d, J = 3.6 Hz, 2H), 5.191 (s, 1H), 4.280 (s, 1H), 3.889 (s, 3H), 2.988 (d, J = 18.7 Hz, 1H), 2.766 (dtd, J = 47.8, 12.1, 5.1 Hz, 2H), 2.004 (d, J = 16.2 Hz, 1H), 1.385 (s, 18H). 13 C NMR (100 MHz, CDCl3) δ 194.2, 169.2, 156.7, 153.4, 150.9, 136.6, 131.8, 130.9, 129.4, 128.9, 128.5, 127.5, 124.7, 124.5, 124.4, 120.0, 116.94 114.8, 56.9, 55.8, 47.2, 34.6, 30.3, 26.4, 18.6. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O5Na 535.2460, found 535.2459. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol−hexane = 1:9), 1.0 mL/min; minor isomer, t1 = 23.69 min, t2 = 29.70 min. [α]25 D 226.7 (c 1.0, CHCl3). (3S,4S)-6-bromo-4-(3,5-ditert-butyl-4-hydroxyphenyl)-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ae). White solid, 110.1 mg; 98% yield; mp 113−115 °C. 1H NMR (400 MHz, CDCl3) δ 7.961 (d, J = 2.4 Hz, 1H), 7.620 (dt, J = 8.2, 1.8 Hz, 1H), 7.290−7.147 (m, 3H), 7.084−6.948 (m, 4H), 5.211 (s, 1H), 4.311 (s, 1H), 3.050 (ddd, J = 17.1, 11.8, 4.7 Hz, 1H), 2.936−2.827 (m, 1H), 2.730 (td, J = 13.2, 12.4, 5.1 Hz, 1H), 2.003 (d, J = 18.8 Hz, 1H), 1.387 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 192.4, 168.5, 153.5, 150.7, 141.5, 137.0, 136.7, 131.8, 131.3, 130.7, 129.0, 128.9, 128.6, 124.9, 124.5, 124.1, 121.2, 117.0, 56.8, 47.2, 34.6, 30.3, 26.9, 24.1. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C32H33BrO4Na 583.1460, found 583.1460. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol−hexane = 1:9), 1.0 mL/min; minor isomer, t1 = 10.16 min, t2 = 16.04 min. [α]25 D 192.1 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-7′-methyl-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3af). White solid, 52.4 mg; 83% yield; mp 178−180 °C. 1H NMR (400 MHz, CDCl3) δ 7.647 (s, 1H), 7.341 (d, J = 7.9 Hz, 1H), 7.280−7.149 (m, 3H), 7.039 (s, 2H), 6.980 (s, 2H), 5.189 (s, 1H), 4.310 (s, 1H), 3.094 (t, J = 15.2 Hz, 1H), 2.958−2.693 (m, 2H), 2.299 (s, 3H), 1.983 (dd, J = 12.1, 7.9 Hz, 1H), 1.386 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 194.0, 169.1, 153.4, 150.8, 139.9, 137.0, 136.6, 135.2, 129.9, 129.5, 128.9, 128.8, 128.7, 128.6, 124.7, 124.4, 116.9, 57.0, 47.3, 34.6, 30.3, 27.3, 27.0, 24.1, 21.0. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O4Na 519.2511, found 519.2510. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol− hexane = 1:9), 1.0 mL/min; minor isomer, t1 = 14.04 min, t2 = 29.99 min. [α]25 D 180.6 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-7′-phenyl-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3ag). White solid, 100.6 mg; 90% yield; mp 113−115 °C. 1H NMR (400 MHz, 2721
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry CDCl3) δ 8.090 (s, 1H), 7.773 (d, J = 8.1 Hz, 1H), 7.547 (d, J = 8.2 Hz, 2H), 7.458−7.178 (m, 6H), 7.031 (d, J = 25.0 Hz, 4H), 5.203 (s, 1H), 4.368 (s, 1H), 3.172 (d, J = 28.7 Hz, 1H), 2.950 (d, J = 17.1 Hz, 1H), 2.896−2.742 (m, 1H), 2.024 (d, J = 17.7 Hz, 1H), 1.396 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 193.7, 169.0, 153.5, 150.9, 141.6, 140.3, 139.6, 136.7, 132.8, 130.5, 129.5, 129.4, 129.0, 129.0, 128.7, 127.9, 127.0, 128.0, 124.8, 124.5, 124.4, 117.0, 57.1, 47.3, 34.6, 30.4, 27.2, 24.3. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C38H38O4Na 581.2668, found 581.2665. The enantiomeric excess was determined by HPLC with an IF column at 210 nm (2-propanol− hexane = 1:9), 1.0 mL/min; minor isomer, t1 = 15.51 min, t2 = 19.01 min; minor isomer, t1 = 16.50 min, t2 = 23.62 min. [α]25 D 218.2 (c 1.0, CHCl3). (4′S,6S)-4′-(3,5-ditert-butyl-4-hydroxyphenyl)-8,9-dihydrospiro[benzo[7]annulene-6,3′-chromane]-2′,5(7H)-dione (3ah). White solid, 74.5 mg; 75% yield; mp 196−198 °C. 1H NMR (400 MHz, CDCl3) δ 7.315 (dt, J = 23.6, 7.8 Hz, 2H), 7.224−7.128 (m, 2H), 7.040 (dt, J = 21.2, 7.5 Hz, 2H), 6.889 (s, 2H), 6.827 (d, J = 7.5 Hz, 1H), 6.310 (d, J = 7.6 Hz, 1H), 5.161 (s, 1H), 4.183 (s, 1H), 2.935 (dddd, J = 20.4, 15.6, 12.1, 4.1 Hz, 2H), 2.401 (ddd, J = 14.9, 9.6, 5.4 Hz, 1H), 2.093−1.948 (m, 2H), 1.904−1.778 (m, 1H), 1.348 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 205.9, 168.8, 153.4, 151.0, 138.9, 137.6, 136.4, 131.2, 129.3, 129.1, 129.0, 128.1, 127.1, 126.3, 125.3, 125.1, 124.6, 117.2, 64.5, 48.6, 35.3, 34.5, 31.3, 30.3, 23.1. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O4Na 519.2511, found 519.2510. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol−hexane = 1:9), 1.0 mL/ min; minor isomer: t1 = 15.57 min, t2 = 20.55 min. [α]25 D 163.1 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)spiro[chromane-3,2′indene]-1′,2(3′H)-dione (3ai). Colorless oil, 72.2 mg; 77% yield. 1H NMR (400 MHz, CDCl3) δ 7.679−7.558 (m, 2H), 7.418−7.284 (m, 3H), 7.197 (dd, J = 8.1, 1.1 Hz, 1H), 7.160−7.069 (m, 2H), 6.933 (s, 2H), 5.164 (s, 1H), 4.227 (s, 1H), 3.759 (d, J = 17.6 Hz, 1H), 3.116 (d, J = 17.6 Hz, 1H), 1.359 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 199.0, 167.0, 153.4, 152.3, 151.3, 136.6, 135.8, 133.8, 129.9, 128.9, 128.7, 128.1, 126.3, 125.3, 124.9, 124.9, 124.7, 116.6, 60.7, 49.6, 35.2, 34.5, 30.3. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C31H32O4Na 491.2198, found 491.2198. The enantiomeric excess was determined by HPLC with an IF column at 210 nm (2-propanol−hexane = 1:9), 1.0 mL/min; major isomer, t1 = 11.26 min, t2 = 12.81 min; minor isomer, t1 = 19.41 min, t2 = 21.32 min. [α]25 D 190.8 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-4′-methyl-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalene]-1′,2-dione (3aj). White solid, 93.4 mg; 94% yield; mp 89−91 °C. 1H NMR (400 MHz, CDCl3) δ 7.962 (d, J = 7.8 Hz, 1H), 7.497 (t, J = 7.7 Hz, 1H), 7.289 (td, J = 12.9, 6.4 Hz, 3H), 7.116 (d, J = 9.3 Hz, 3H), 7.020 (s, 2H), 5.213 (s, 1H), 5.159 (s, 1H), 3.282 (dt, J = 12.2, 5.6 Hz, 1H), 2.123 (dd, J = 13.9, 4.1 Hz, 1H), 1.970−1.869 (m, 1H), 1.369 (s, 18H), 1.326 (d, J = 6.6 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 193.1, 167.9, 153.3, 150.8, 147.3, 135.5, 133.9, 132.2, 129.3, 128.4, 128.3, 128.1, 126.8, 126.1, 125.8, 125.0, 124.6, 116.4, 57.1, 47.4, 35.3, 34.4, 30.5, 28.9, 20.0. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C33H36O4Na 519.2511, found 519.2511. The enantiomeric excess was determined by HPLC with an IC column at 210 nm (2-propanol− hexane = 1:9), 1.0 mL/min; major isomer, t1 = 12.13 min, t2 = 17.22 min; minor isomer, t1 = 7.87 min, t2 = 13.58 min. [α]25 D 66.2 (c 1.0, CHCl3). (3S,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)spiro[chromane-3,1′cyclohexane]-2,2′-dione (3ak). White solid, 73.0 mg; 84% yield; mp 185−187 °C. 1H NMR (400 MHz, CDCl3) δ 7.283−7.209 (m, 1H), 7.143 (t, J = 6.6 Hz, 2H), 7.037 (t, J = 7.5 Hz, 1H), 6.938 (s, 2H), 5.183 (s, 1H), 4.487 (s, 1H), 2.684 (td, J = 12.5, 5.8 Hz, 1H), 2.320 (dd, J = 13.6, 4.3 Hz, 1H), 2.236 (ddd, J = 14.9, 10.6, 5.1 Hz, 1H), 2.115 (d, J = 11.8 Hz, 1H), 1.971−1.691 (m, 4H), 1.367 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 207.4, 168.6, 153.7, 150.9, 136.5, 129.2, 128.4, 127.6, 124.9, 124.7, 124.6, 117.0, 62.6, 48.0, 38.4, 34.5, 32.2, 30.3, 28.4, 20.5. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C28H34O4Na 457.2355, found 457.2352. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol−
hexane = 1:19), 1.0 mL/min; major isomer, 1.0 mL/min; major isomer, t1 = 7.60 min, t2 = 9.24 min. [α]25 D 222.5 (c 1.0, CHCl3). Gram Scale Reaction of Asymmetric Synthesis of 3aa. To a stirred solution of p-QM 1a (931.2 mg, 3.0 mmol, 1.0 equiv) and 1oxotetralin-2-carbaldehyde 2a (783.9 mg, 3.0 mmol, 1.5 equiv) in dry CHCl3 (30 mL) at room temperature was added catalyst B (0.3 mmol). The reaction was monitored by TLC. After 1a was consumed completely, the reaction solution was concentrated in vacuo and the crude product was purified by flash chromatography eluting with petroleum ether−ethyl acetate 5:1) to afford the product 3a′ (1.32 g, 91% yield, 1.2 dr). Then, DMP (1.53 g, 1.5 equiv) was added to a solution of 3a′ (1.16 g, 2.4 mmol, 1.0 equiv) in 50 mL of CH2Cl2 and the reaction was monitored by TLC. The reaction solution was concentrated in vacuo after 1 h, and the crude product was purified by flash chromatography eluting with petroleum ether−ethyl acetate 10:1) to afford the products 3aa (1.07 g, 92% yield, >19:1dr, 99% ee). Synthesis of 4a′.19a Under Ar atmosphere, a solution of 3a′ (48.5 mg, 0.1 mmol) and TEA (21 μL, 0.15 mmol, 1.5 equiv) in CH2Cl2 (5 mL) at 0 °C was added drowise acetyl chloride (10.5 μL 0.15 mmol, 1.5 equiv). The resulting mixture was stirred 30 min until completion of the reaction at 0 °C, then the reaction was quenched with saturated aqueous NaHCO3 and extracted with CH2Cl2. The organic phase was dried over Na2SO4 and concenterated under reduced pressure. The crude residue was purified with silica gel by column chromatography (hexane−ethyl acetate 20:1) afforded 4a′ as a colorless oil (51.1 mg, 97% yield, 1.2:1 dr, 99%/98% ee). (3R,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-1′-oxo-3′,4′-dihydro-1′H-spiro[chromane-3,2′-naphthalen]-2-yl acetate (4a′). White solid, 51.1 mg; 97% yield; mp 88−91 °C. 1H NMR (400 MHz, CDCl3) δ 8.024−7.934 (m, 1H), 7.470−7.351 (m, 1H), 7.299−7.110 (m, 3H), 7.032−6.887 (m, 3H), 6.852 (s, 1H), 6.577 (d, J = 47.0 Hz, 1H), 5.260 (d, J = 126.3 Hz, 1H), 5.071 (d, J = 8.6 Hz, 1H), 3.405− 1.896 (m, 7H), 1.362 (s, 8H), 1.234 (s, 10H). 13C NMR (100 MHz, CDCl3) δ 199.4, 194.4, 169.8, 168.8, 153.0, 152.7, 152.6, 150.3, 144.2, 142.6, 135.4, 134.8, 133.7, 133.6, 133.0, 132.3, 130.9, 130.6, 129.3, 129.2, 129.1, 128.5, 128.4, 127.9, 127.6, 127.5, 127.0, 126.5, 125.1, 124.0, 122.0, 121.7, 117.1, 117.0, 95.2, 89.4, 50.6, 50.4, 49.7, 41.6, 34.4, 34.3, 30.6, 30.3, 26.4, 25.0, 24.9, 22.2, 21.1, 21.0. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C34H38O5Na 549.2617, found 549.2615. The enantiomeric excess was determined by HPLC with an IA column at 210 nm (2-propanol−hexane = 1:19), 1.0 mL/min; major isomer, t1 = 5.87 min, t2 = 7.60 min; minor isomer, t1 = 4.83 min, t2 = 5.32 min. [α]25 D 84.8 (c 0.5, CHCl3). Synthesis of 5a′.19b Under Ar atmosphere, a solution of 3a′ (97.0 mg, 0.2 mmol) and triethylsilane (96 μL, 0.6 mmol, 3.0 equiv) in CH2Cl2 (5 mL) at −78 °C was added trifluoroborane diethyl etherate (74 μL 0.4 mmol, 2.0 equiv). After it was stirred at −78 °C for 1 h, the reaction mixture was slowly raised to room temperature. The resulting mixture was stirred 12 h until completion of the reaction, then the reaction was quenched with saturated aqueous NaHCO3 and extracted with CH2Cl2. The organic phase was dried over Na2SO4 and concentrated under reduced pressure. The crude residue was purified with silica gel by column chromatography (hexane−ethyl acetate 10:1) afforded 5a′ as a yellow solid (56.2 mg, 60% yield, >19:1 dr, 99% ee). (3R,4S)-4-(3,5-ditert-butyl-4-hydroxyphenyl)-3′,4′-dihydro-1′Hspiro[chromane-3,2′-naphthalen]-1′-one (5a’). Yellow solid, 56.2 mg; 60% yield; mp 145−147 °C. 1H NMR (400 MHz, CDCl3) δ 8.009 (d, J = 7.8 Hz, 1H), 7.506−7.392 (m, 1H), 7.285 (d, J = 7.6 Hz, 1H), 7.146 (dd, J = 13.0, 7.5 Hz, 2H), 7.046 (d, J = 7.7 Hz, 1H), 6.950−6.818 (m, 4H), 5.223 (s, 1H), 5.050 (s, 1H), 4.299 (d, J = 11.1 Hz, 1H), 4.033 (d, J = 11.0 Hz, 1H), 3.059 (ddd, J = 16.8, 11.7, 4.7 Hz, 1H), 2.648 (dt, J = 17.4, 4.5 Hz, 1H), 2.048 (dt, J = 13.9, 4.5 Hz, 1H), 1.924−1.780 (m, 1H), 1.317 (s, 18H). 13C NMR (100 MHz, CDCl3) δ 198.5, 154.4, 152.6, 143.5, 135.0, 133.6, 132.5, 131.3, 130.7, 128.8, 128.0, 127.6, 127.3, 126.8, 124.9, 120.9, 116.4, 68.8, 48.7, 47.2, 34.3, 30.5, 25.2, 25.0. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C32H36O3Na 491.2562, found 491.2560. The enantiomeric excess was determined by HPLC with an IA column at 210 nm (2-propanol− hexane = 1:49), 1.0 mL/min; major isomer, t1 = 4.98 min, t2 = 7.72 min. [α]25 D 55.8 (c 0.5, CHCl3). 2722
DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
Article
The Journal of Organic Chemistry Synthesis of 4aa.19c Under Ar atmosphere, 3aa (97 mg, 0.2 mmol) was dissolved in 10.0 mL of anhydrous toluene, then 10:1 Tf2O−TfOH (10:1 v/v) 10 μL was added dropwise. The resulting mixture stirred for 12 h at 60 °C. Then 10 mL of H2O was added to quenched the reaction and extracted with ethyl acetate. The organic phase was dried over Na2SO4 and concentrated under reduced pressure. The crude residue was purified with silica gel by column chromatography (hexane−ethyl acetate 3:1) afforded 4aa as a white solid (60.0 mg, 81% yield, >19:1 dr, racemic). 4-(4-Hydroxyphenyl)-3′,4′-dihydro-1′H-spiro[chromane-3,2′naphthalene]-1′,2-dione (4aa). White solid, 60.0 mg; 81% yield; mp 237−239 °C. 1H NMR (400 MHz, DMSO-d6) δ 9.546 (s, 1H), 7.772−7.595 (m, 2H), 7.430 (d, J = 7.7 Hz, 1H), 7.405−7.318 (m, 1H), 7.287 (ddd, J = 8.6, 7.3, 1.6 Hz, 1H), 7.214 (d, J = 8.2 Hz, 1H), 7.191−7.098 (m, 3H), 7.069−6.961 (m, 1H), 6.737 (d, J = 8.6 Hz, 2H), 4.603 (s, 1H), 3.166 (ddd, J = 17.6, 12.7, 4.6 Hz, 1H), 2.908 (d, J = 18.2 Hz, 1H), 2.650 (td, J = 13.5, 5.0 Hz, 1H), 1.822 (dd, J = 10.6, 3.7 Hz, 1H). 13C NMR (100 MHz, DMSO-d6) δ 193.9, 168.5, 156.9, 150.1, 143.4, 134.6, 129.5, 129.4, 129.1, 128.7, 128.6, 127.6, 127.2, 124.8, 124.7, 116.4, 116.0, 56.4, 44.4, 27.1, 23.4. HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C24H18O4Na 393.1103, found 393.1102. The enantiomeric excess was determined by HPLC with an AD-H column at 210 nm (2-propanol−hexane = 1:2), 1.0 mL/min; major isomer, t1 = 6.85 min, t2 = 7.53 min; major isomer, t1 = 8.83 min, t2 = 9.70 min.
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.joc.7b03177. 1 H NMR, 13C NMR, and HPLC spectra and X-ray crystallography data for 3af, 3ah, and 3ak (PDF) Crystallography data for 3m (CIF) Crystallography data for 3o (CIF) Crystallography data for 3r (CIF)
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. ORCID
Li Chen: 0000-0001-8820-1496 Xin Li: 0000-0001-6020-9170 Jin-Pei Cheng: 0000-0001-8822-1577 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS We are grateful to the NNSFC (Grant Nos. 21390400 and 21421062) and Nankai University for financial support. REFERENCES
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DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724
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DOI: 10.1021/acs.joc.7b03177 J. Org. Chem. 2018, 83, 2714−2724