Letter Cite This: Org. Lett. 2019, 21, 5600−5605
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Metal-Free Cyclopropanol Ring-Opening C(sp3)−C(sp2) CrossCouplings with Aryl Sulfoxides Dengfeng Chen,† Yuanyuan Fu,† Xiaoji Cao,‡ Jinyue Luo,† Fei Wang,† and Shenlin Huang*,† †
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Jiangsu Provincial Key Lab for the Chemistry and Utilization of Agro-Forest Biomass, College of Chemical Engineering, Jiangsu Key Lab of Biomass-Based Green Fuels and Chemicals, Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, P. R. China ‡ College of Chemical Engineering, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, Zhejiang 310014, P. R. China S Supporting Information *
ABSTRACT: A metal-free method for formal β-arylation/ heteroarylation of ketones through efficient cyclopropanol ring-opening cross-couplings with aryl sulfoxides at room temperature has been developed. This protocol shows a broad substrate scope and promising scalability. In addition, the utility of the β-arylated ketones is further demonstrated through a variety of postcoupling transformations and synthetic applications. Scheme 1. Preparation of β-Arylated Ketones
β-Arylated/heteroarylated ketones are frequently found in many bioactive molecules and natural products.1 Traditionally, they are often accessed via the Michael addition of aryl nucleophiles to α,β-unsaturated ketones;2 however, these reactions often require the preformed organometallic reagents and enones or harsh reaction conditions. As a result, a number of novel approaches to address their syntheses have recently emerged. In 2013, MacMillan disclosed a direct β-arylation of cyclic ketones via merging photoredox and enamine catalysis, in which electron-deficient dicyanobenzene was employed as the aryl source.3 Arguably, the most common method involves noble transition-metal-catalyzed direct β-arylation of ketones with aryl carboxylic acids,4 arylboronic acids,5 diaryliodonium salts,6 and aryl iodides,7 via either direct β-C(sp3)−H activation or ketone dehydrogenation/conjugate addition (Scheme 1A). Alternatively, β-arylated ketones can be accessed by the palladium-catalyzed coupling of cyclopropanols, known as homoenolate precursors, with aryl bromides (Scheme 1B).8 Nonetheless, these efforts are still plagued by at least one of the following limitations: (1) the use of a sophisticated photocatalysis setup, (2) the use of expensive transition metals, (3) the necessity of prefunctionalized coupling partners, (4) the need for high reaction temperatures, and (5) a narrow heteroarylation scope. Thus despite remarkable recent advances in the direct β-arylation of ketones, a metal-free approach to β-arylated/heteroarylated ketones under mild conditions that avoids metal contamination of products, especially in the pharmaceutical industry,9 would be highly desirable and challenging. With our continuous interest in exploring sustainable synthetic transformations,10 we present herein a metal-free method for the formal β-arylation/heteroarylation of ketones through a Pummerer-like reaction11 of cyclopropanols and aryl sulfoxides at room temperature. The starting material, © 2019 American Chemical Society
cyclopropanols,12 a versatile building block that has found diverse applications,13 are readily available from the Simmons− Smith reaction or the Kulinkovich reaction. We envisioned that cyclopropanols could serve as a nucleophile to react with the activated sulfoxides A through a Pummerer-type mechanism (Scheme 1C). Rearomatization of aryl/heteroaryl sulfonium intermediates B would eventually give rise to the desired βarylated/heteroarylated ketones. The products, especially βheteroarylated ketones, are challenging targets for previous transition-metal-catalyzed methods. Initial investigations focused on the reaction of 1-phenylcyclopropan-1-ol 1a with 2-methylsulfinyl naphthalene 2a to Received: June 6, 2019 Published: July 3, 2019 5600
DOI: 10.1021/acs.orglett.9b01908 Org. Lett. 2019, 21, 5600−5605
Letter
Organic Letters
Notably, the “normal” Pummerer product 3a′ was not observed. We next examined other activators, as shown in entries 2−4 of Table 1, revealing that perfluoropropionic anhydride (PFPA) was the optimal activator. Furthermore, various additives were evaluated with PFPA as the activator at room temperature. The reaction did not take place in the presence of more acidic TfOH (entry 5), which suggested that pentafluoropropionic acid (CF3CF2CO2H), formed as the reaction proceeds, might decrease the reaction efficiency.14 Hence, 2,6-lutidine or Et3N was used to decrease the concentration of CF3CF2CO2H in the reaction mixture. Unfortunately, inferior reaction performance was observed (entries 6 and 7). Gratifyingly, an improved yield (72%) was obtained with 2.0 equiv of CF3CO2Na (entry 11), whereas lower (entries 9 and 10) or higher amounts (entries 12 and 13) of CF3CO2Na led to decreased yields. For further improvement of reaction performance, different types of molecular sieves were examined. The use of 5 Å molecular sieves proved ideal (entry 16), with either 3 or 4 Å molecular sieves leading to decreased yields (entries 14 and 15). Sodium trifluoroacetate and molecular sieves might serve as a buffer for the pentafluoropropionic acid generated in the reaction or simply as a desiccant. Finally, the reaction efficiency was reduced upon removing CF3CO2Na from the reaction (entry 17) or replacing PFPA with TFAA (entry 18). With the optimized reaction conditions in hand, we next explored the scope of sulfoxides amenable to this crosscoupling reaction (Scheme 2). 2-Methylsulfinyl naphthalene 2a underwent efficient coupling to both 1-phenyl-substituted cyclopropanol 1a and 1-(naphthalen-2-yl)-substituted cyclopropanol 1b to give the desired products 3a and 3b in good isolated yield. 2-(p-Tolylsulfinyl) naphthalene has also been successfully coupled to 1b to provide 3c in 67% yield. Notably, diphenyl sulfoxide successfully reacted with 1a to afford the
generate β-arylated 1-phenylpropan-1-one 3a. We were pleased to find that with trifluoroacetic anhydride (TFAA) as the activator, this reaction provided a 52% yield of the desired product 3a after 8 h at room temperature (Table 1, entry 1). Table 1. Optimization of the Reaction Conditionsa
entry
anhydride
additive (equiv)
yield (%)b
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
TFAA Tf2O Ts2O PFPA PFPA PFPA PFPA PFPA PFPA PFPA PFPA PFPA PFPA PFPA PFPA PFPA PFPA TFAA
none none none none TfOH (1.5) 2,6-lutidine (1.5) Et3N (1.5) NaOTf (1.5) CF3CO2Na (1.0) CF3CO2Na (1.5) CF3CO2Na (2.0) CF3CO2Na (2.5) CF3CO2Na (3.0) CF3CO2Na (2.0), 3 Å MSc CF3CO2Na (2.0), 4 Å MSc CF3CO2Na (2.0), 5 Å MSc 5 Å MSc CF3CO2Na (2.0), 5 Å MSc
52 0 0 57 0 27 17 60 63 67 72 60 33 57 49 75 59 61
a
Reaction conditions: Anhydride (0.2 mmol) was added to a mixture of 1a (0.1 mmol) and 2a (0.2 mmol) in CH2Cl2 (0.1 M) at rt. b HPLC yield with 1-nitronaphthalene as the internal standard. c0.05 g/mmol.
Scheme 2. Scope of Sulfoxidesa,b
a
Reaction conditions: 1 (0.2 mmol), 2 (0.4 mmol), CF3COONa (0.4 mmol), 5 Å MS (10 mg), DCM (2 mL), followed by (CF3CF2CO)2O (0.4 mmol). bIsolated yield. c70 °C for 8 h. 5601
DOI: 10.1021/acs.orglett.9b01908 Org. Lett. 2019, 21, 5600−5605
Letter
Organic Letters
reaction was observed with 1-methyl-2-phenylcyclopropan-1ol. To highlight the practicality of this coupling, a 5.0 mmol scale synthesis was carried out to give 4a in 83% yield (Scheme 4a). Moreover, the transformations of β-arylated ketone 3a are
desired product 3d, albeit in a suboptimal 34% yield. Phenyl sulfoxides bearing electron-donating group(s) at the meta position(s) exhibited better reactivity to give the desired products 3e−3g, perhaps due to the fact that the electrondonating group(s) at the meta position(s) could stabilize the cationic intermediate B in Scheme 1C to facilitate the addition of cyclopropanol to aryl sulfonium A.15 Interestingly, the coupling took place selectively on the m-tolyl ring to deliver 3g, whereas the thiophene unit remained intact. On the contrary, the coupling reaction occurred at the thiophene ring instead of the o-tolyl or p-tolyl ring (3h and 3i). In the reaction of unsymmetrical diaryl sulfoxides, cyclopropanols were generally coupled to the naphthalene or thiophene unit with weaker aromaticity (3c and 3h−k). The selectivity of the coupling was further confirmed by single-crystal X-ray analysis of 3k. Furthermore, a variety of alkylsulfinyl-substituted thiophenes underwent regioselective coupling with cyclopropanols 1a and 1b to provide 3l−t in good yield. Importantly, complex trans-androsterone derivative 3v proved to be an exceptional coupling product. Additionally, 3dodecylsulfinyl thiophene was also a suitable substrate, affording the C2-substituted product 3u in 59% yield. Finally, other heterocyclic coupling partners also reacted smoothly with cyclopropanols to give β-heteroarylated ketones 3w−y in moderate to good yield. Next, we proceeded to explore the scope of cyclopropanols (Scheme 3). A variety of aryl-substituted cyclopropanols
Scheme 4. Gram-Scale Reaction and Synthetic Applications
Scheme 3. Scope of Cyclopropanolsa,b
presented in Scheme 4b, thus further demonstrating the synthetic utility of this method. Copper-catalyzed dehydrogenation16 of ketone 3a generated enone 6 in 73% yield. The Wittig reaction worked well, affording olefin 7 in 72% yield. The reduction of ketone functionality proceeded smoothly with NaBH4 to give alcohol 8 in 98% yield. In addition to ketone elaboration, the sulfide group of 3a could also be further manipulated. The oxidation of sulfide with 1 or 3 equiv m-CPBA delivered sulfoxide 9a or sulfone 9b in excellent yield, respectively.17 Furthermore, the methylthio substituent could be easily excised by reduction with Ni(cod)2/EtMe2SiH in toluene,18 leading to desulfurized product 10 in excellent yield. Finally, ketone 10 was conveniently converted to 1,3-diketone 11, indole 12, alkane 13, enone 14, isoxazole 15, and 4,5dihydro-1H-pyrazole 16. Finally, several control experiments were conducted (see Supporting Information (SI)), indicating that the PFPA is required to activate sulfoxides for the desired coupling reaction. In addition, an in situ nuclear magnetic resonance (NMR) study on the reaction of cyclopropanol 1b and sulfoxide 2b was performed (see the SI). Pleasingly, Osulfenylated intermediate II was observed (Scheme 5). As expected, intermediate II is unstable and undergoes either a [3,3]-sigmatropic rearrangement or an intramolecular nucleophilic addition19 to afford sulfonium III, which provides βarylated ketone 3q after aromatization. In summary, we have described an efficient method to access β-arylated/heteroarylated ketones via a metal-free coupling of cyclopropanols and aryl sulfoxides at room temperature. This
a
Reaction conditions: 1 (0.2 mmol), 2 (0.4 mmol), CF3COONa (0.4 mmol), 5 Å MS (10 mg), DCM (2 mL), followed by (CF3CF2CO)2O (0.4 mmol). bIsolated yield.
underwent the desired coupling with 2-propylsulfinyl thiophene 2b to afford various β-heteroarylated ketones 4a−j in good to excellent yield. Notably, functional groups such as ester (4a), trifluoromethyl (4b), alkyl (4c, 4d, and 4j), 4methylbenzenesulfonate (4e), fluoride (4f), chloride (4g), and bromide (4h and 4i) are well tolerated. Note that aryl halides, not compatible with transition-metal-mediated cross couplings, can be tolerated under the standard conditions, which could be potentially further functionalized. 1-(6-Bromonaphthalen-2-yl) cyclopropan-1-ol was also compatible under the standard conditions, delivering the desired product 4k in 53% yield. Moreover, alkyl-substituted cyclopropanols also participated in this coupling reaction, leading to the desired products 4l−p in moderate to good yield. Unfortunately, no desired coupling 5602
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Myrica gale and structurally related acetophenones. Free Radical Biol. Med. 1997, 22, 307. (2) (a) Fagnou, K.; Lautens, M. Rhodium-catalyzed carbon−carbon bond forming reactions of organometallic compounds. Chem. Rev. 2003, 103, 169. (b) Hayashi, T.; Yamasaki, K. Rhodium-catalyzed asymmetric 1,4-addition and its related asymmetric reactions. Chem. Rev. 2003, 103, 2829. (3) Pirnot, M. T.; Rankic, D. A.; Martin, D. B. C.; MacMillan, D. W. C. Photoredox activation for the direct β-arylation of ketones and aldehydes. Science 2013, 339, 1593. (4) Li, H.; Jiang, Q.; Jie, X.; Shang, Y.; Zhang, Y.; Goossen, L. J.; Su, W. Rh/Cu-catalyzed ketone β-functionalization by merging ketone dehydrogenation and carboxyl-directed C−H alkylation. ACS Catal. 2018, 8, 4777. (5) Hu, X.; Yang, X.; Dai, X.-J.; Li, C.-J. Palladium-catalyzed direct β-C-H arylation of ketones with arylboronic acids in water. Adv. Synth. Catal. 2017, 359, 2402. (6) Huang, Z.; Sam, Q. P.; Dong, G. Palladium-catalyzed direct βarylation of ketones with diaryliodonium salts: a stoichiometric heavy metal-free and user-friendly approach. Chem. Sci. 2015, 6, 5491. (7) (a) Huang, Z.; Dong, G. Catalytic direct β-arylation of simple ketones with aryl iodides. J. Am. Chem. Soc. 2013, 135, 17747. (b) Zhang, F.-L.; Hong, K.; Li, T.-J.; Park, H.; Yu, J.-Q. Functionalization of C(sp3)−H bonds using a transient directing group. Science 2016, 351, 252. (c) Zhu, R.-Y.; Liu, L.-Y.; Park, H. S.; Hong, K.; Wu, Y.; Senanayake, C. H.; Yu, J.-Q. Versatile alkylation of (hetero)aryl iodides with ketones via β-C(sp3)−H activation. J. Am. Chem. Soc. 2017, 139, 16080. (8) Rosa, D.; Orellana, A. Palladium-catalyzed cross-coupling of cyclopropanol-derived ketone homoenolates with aryl bromides. Chem. Commun. 2013, 49, 5420. (9) (a) Garrett, C. E.; Prasad, K. The art of meeting palladium specifications in active pharmaceutical ingredients produced by Pdcatalyzed reactions. Adv. Synth. Catal. 2004, 346, 889. (b) Rosso, V. W.; Lust, D. A.; Bernot, P. J.; Grosso, J. A.; Modi, S. P.; Rusowicz, A.; Sedergran, T. C.; Simpson, J. H.; Srivastava, S. K.; Humora, M. J.; Anderson, N. G. Removal of palladium from organic reaction mixtures by trimercaptotriazine. Org. Process Res. Dev. 1997, 1, 311. (10) (a) Chen, D.; Feng, Q.; Yang, Y.; Cai, X.-M.; Wang, F.; Huang, S. Metal-free O−H/C−H difunctionalization of phenols by ohydroxyarylsulfonium salts in water. Chem. Sci. 2017, 8, 1601. (b) Feng, Q.; Chen, D.; Hong, M.; Wang, F.; Huang, S. Phenyliodine(III) bis(trifluoroacetate) (PIFA)-mediated synthesis of aryl sulfides in water. J. Org. Chem. 2018, 83, 7553. (c) Chen, D.; Zhang, Y.; Pan, X.; Wang, F.; Huang, S. Oxidation of tertiary aromatic alcohols to ketones in water. Adv. Synth. Catal. 2018, 360, 3607. (d) Yang, Y.; Meng, X.; Zhu, B.; Jia, Y.; Cao, X.; Huang, S. A micellar catalysis strategy for amidation of alkynyl bromides: synthesis of ynamides in water. Eur. J. Org. Chem. 2019, 2019, 1166. (11) For reviews, see: Bur, S. K.; Padwa, A. The Pummerer reaction: methodology and strategy for the synthesis of heterocyclic compounds. Chem. Rev. 2004, 104, 2401. (b) Feldman, K. S. Modern Pummerer-type reactions. Tetrahedron 2006, 62, 5003. (c) Smith, L. H. S.; Coote, S. C.; Sneddon, H. F.; Procter, D. J. Beyond the Pummerer reaction: recent developments in thionium ion chemistry. Angew. Chem., Int. Ed. 2010, 49, 5832. (d) Pulis, A. P.; Procter, D. J. C−H coupling reactions directed by sulfoxides: teaching an old functional group new tricks. Angew. Chem., Int. Ed. 2016, 55, 9842. (e) Shafir, A. The emergence of sulfoxide and iodonio-based redox arylation as a synthetic tool. Tetrahedron Lett. 2016, 57, 2673. (f) Yorimitsu, H. Cascades of interrupted Pummerer reactionsigmatropic rearrangement. Chem. Rec. 2017, 17, 1156. (g) Yanagi, T.; Nogi, K.; Yorimitsu, H. Recent development of ortho-C−H functionalization of aryl sulfoxides through [3,3] sigmatropic rearrangement. Tetrahedron Lett. 2018, 59, 2951 For selected recent applications, see: . (h) Akai, S.; Morita, N.; Iio, K.; Nakamura, Y.; Kita, Y. Ambident effect of a p-sulfinyl group for the introduction of two carbon substituents to phenol rings: A convergent synthesis of diverse benzofuran Neolignans. Org. Lett. 2000, 2, 2279. (i) Akai, S.;
Scheme 5. Proposed Reaction Mechanism
method was compatible with various aryl sulfoxides and cyclopropanols with a wide range of functional groups and showed promising scalability. Moreover, these resultant βarylated/heteroarylated ketones were demonstrated to be versatile building blocks through a variety of synthetic applications.
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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.orglett.9b01908. Experimental procedures and characterization data (PDF) Accession Codes
CCDC 1886366 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
[email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. ORCID
Shenlin Huang: 0000-0001-7322-6981 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS Financial support was provided by the Natural Science Foundation of China (21502094 and 21602200), and the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (17KJA220003) is acknowledged. We are also grateful for the support of the advanced analysis and testing center of Nanjing Forestry University. D.C. thanks the Doctorate Fellowship Foundation of Nanjing Forestry University and the Postgraduate Research & Practice Innovation Program of Jiangsu Province.
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REFERENCES
(1) (a) Mathiesen, L.; Malterud, E.; Sund, R. B. Antioxidant activity of fruit exudate and C-methylated dihydrochalcones from Myrica gale. Planta Med. 1995, 61, 515. (b) Mathiesen, L.; Malterud, E.; Sund, R. B. Hydrogen bond formation as basis for radical scavenging activity: A structure−activity study of C-methylated dihydrochalcones from 5603
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Organic Letters
couplings with (fluoro)alkyl halides. Org. Lett. 2015, 17, 6074. (f) Zhao, H.; Fan, X.; Yu, J.; Zhu, C. Silver-catalyzed ring-opening strategy for the synthesis of β- and γ-fluorinated ketones. J. Am. Chem. Soc. 2015, 137, 3490. (g) Ren, S.; Feng, C.; Loh, T.-P. Iron- or silvercatalyzed oxidative fluorination of cyclopropanols for the synthesis of β-fluoroketones. Org. Biomol. Chem. 2015, 13, 5105. (h) Murali, R. V. N. S.; Rao, N. N.; Cha, J. K. C-alkynylation of cyclopropanols. Org. Lett. 2015, 17, 3854. (i) Kananovich, D. G.; Konik, Y. A.; Zubrytski, D. M.; Järving, I.; Lopp, M. Simple access to β-trifluoromethylsubstituted ketones via copper-catalyzed ring-opening trifluoromethylation of substituted cyclopropanols. Chem. Commun. 2015, 51, 8349. (j) Zhou, X.; Yu, S.; Kong, L.; Li, X. Rhodium(III)-catalyzed coupling of arenes with cyclopropanols via C−H activation and ring opening. ACS Catal. 2016, 6, 647. (k) Jia, K.; Zhang, F.; Huang, H.; Chen, Y. Visible-light-induced alkoxyl radical generation enables selective C(sp3)−C(sp3) bond cleavage and functionalizations. J. Am. Chem. Soc. 2016, 138, 1514. (l) Davis, D. C.; Walker, K. L.; Hu, C.; Zare, R. N.; Waymouth, R. M.; Dai, M. Catalytic carbonylative spirolactonization of hydroxycyclopropanols. J. Am. Chem. Soc. 2016, 138, 10693. (m) Zhang, H.; Wu, G.; Yi, H.; Sun, T.; Wang, B.; Zhang, Y.; Dong, G.; Wang, J. Copper(I)-catalyzed chemoselective coupling of cyclopropanols with diazoesters: ring-opening C−C bond formations. Angew. Chem., Int. Ed. 2017, 56, 3945. (n) Zhou, X.; Yu, S.; Kong, L.; Li, X. Rhodium(III)-catalyzed coupling of arenes with cyclopropanols via C−H activation and ring opening. ACS Catal. 2016, 6, 647. (o) Ye, Z.; Cai, X.; Li, J.; Dai, M. Catalytic cyclopropanol ring opening for divergent syntheses of γ-butyrolactones and δ-ketoesters containing all-carbon Quaternary centers. ACS Catal. 2018, 8, 5907. (14) Kawashima, H.; Yanagi, T.; Wu, C.-C.; Nogi, K.; Yorimitsu, H. Regioselective C−H sulfanylation of aryl sulfoxides by means of Pummerer-type activation. Org. Lett. 2017, 19, 4552. (15) Yanagi, T.; Otsuka, S.; Kasuga, Y.; Fujimoto, K.; Murakami, K.; Nogi, K.; Yorimitsu, H.; Osuka, A. Metal-free approach to biaryls from phenols and aryl sulfoxides by temporarily sulfur-tethered regioselective C−H/C−H coupling. J. Am. Chem. Soc. 2016, 138, 14582. (16) (a) Jie, X.; Shang, Y.; Zhang, X.; Su, W. Cu-catalyzed sequential dehydrogenation−conjugate addition for β-functionalization of saturated ketones: scope and mechanism. J. Am. Chem. Soc. 2016, 138, 5623. (b) Shang, Y.; Jie, X.; Jonnada, K.; Zafar, S. N.; Su, W. Dehydrogenative desaturation-relay via formation of multicenterstabilized radical intermediates. Nat. Commun. 2017, 8, 2273. (17) The sulfides, sulfoxides, sulfoniums, and sulfones have been proved to be versatile reagents for cross-coupling. For reviews, see: (a) Dubbaka, S. R.; Vogel, P. Organosulfur compounds: electrophilic reagents in transition-metal-catalyzed carbon−carbon bond-forming reactions. Angew. Chem., Int. Ed. 2005, 44, 7674. (b) Wang, L.; He, W.; Yu, Z. Transition-metal mediated carbon−sulfur bond activation and transformations. Chem. Soc. Rev. 2013, 42, 599. (c) Modha, S. G.; Mehta, V. P.; Van der Eycken, E. V. Transition metal-catalyzed C−C bond formation via C−S bond cleavage: an overview. Chem. Soc. Rev. 2013, 42, 5042. (d) Pan, F.; Shi, Z. J. Recent advances in transitionmetal-catalyzed C−S activation: from thioester to (hetero)aryl thioether. ACS Catal. 2014, 4, 280. (e) Gao, K.; Otsuka, S.; Baralle, A.; Nogi, K.; Yorimitsu, H.; Osuka, A. Cross-coupling of aryl sulfides powered by N-heterocyclic carbene ligands. Yuki Gosei Kagaku Kyokaishi 2016, 74, 1119. (f) Otsuka, S.; Nogi, K.; Yorimitsu, H. C−S bond activation. Top. Curr. Chem. 2018, 376, 13. (18) Barbero, N.; Martin, R. Ligand-free Ni-catalyzed reductive cleavage of inert carbon−sulfur bonds. Org. Lett. 2012, 14, 796. (19) (a) Akai, S.; Kawashita, N.; Wada, Y.; Satoh, H.; Alinejad, A. H.; Kakiguchi, K.; Kuriwaki, I.; Kita, Y. Regioselective, nucleophilic carbon−carbon bond formation at the C4-position of indoles initiated by the aromatic Pummerer-type reaction. Tetrahedron Lett. 2006, 47, 1881. (b) Feldman, K. S.; Vidulova, D. B. Extending Pummerer Reaction Chemistry. Application to the Oxidative Cyclization of Indole Derivatives. Org. Lett. 2004, 6, 1869. (c) Feldman, K. S.; Skoumbourdis, A. P. Extending Pummerer Reaction Chemistry. Synthesis of (±)-Dibromophakellstatin by Oxidative Cyclization of an
Kawashita, N.; Satoh, H.; Wada, Y.; Kakiguchi, K.; Kuriwaki, I.; Kita, Y. Highly regioselective nucleophilic carbon−carbon bond formation on furans and thiophenes initiated by Pummerer-type reaction. Org. Lett. 2004, 6, 3793. (j) Huang, X.; Maulide, N. Sulfoxide-mediated αarylation of carbonyl compounds. J. Am. Chem. Soc. 2011, 133, 8510. (k) Eberhart, A. J.; Imbriglio, J. E.; Procter, D. J. Nucleophilic ortho allylation of aryl and heteroaryl sulfoxides. Org. Lett. 2011, 13, 5882. (l) Huang, X.; Patil, M.; Farès, C.; Thiel, W.; Maulide, N. Sulfur(IV)mediated transformations: from ylide transfer to metal-free arylation of carbonyl compounds. J. Am. Chem. Soc. 2013, 135, 7312. (m) Eberhart, A. J.; Cicoira, C.; Procter, D. J. Nucleophilic orthoallylation of pyrroles and pyrazoles: An accelerated Pummerer/thioClaisen rearrangement sequence. Org. Lett. 2013, 15, 3994. (n) Eberhart, A. J.; Procter, D. J. Nucleophilic ortho-propargylation of aryl sulfoxides: An interrupted Pummerer/allenyl thio-Claisen rearrangement sequence. Angew. Chem., Int. Ed. 2013, 52, 4008. (o) Fernández-Salas, J. A.; Eberhart, A. J.; Procter, D. J. Metal-free CH−CH-type cross-coupling of arenes and alkynes directed by a multifunctional sulfoxide group. J. Am. Chem. Soc. 2016, 138, 790. (p) Eberhart, A. J.; Shrives, H.; Zhang, Y.; Carrër, A.; Parry, A. V. S.; Tate, D. J.; Turner, M. L.; Procter, D. J. Sulfoxide-directed metal-free cross-couplings in the expedient synthesis of benzothiophene-based components of materials. Chem. Sci. 2016, 7, 1281. (q) Shrives, H. J.; Fernández-Salas, J.; Hedtke, C.; Pulis, A. P.; Procter, D. J. Regioselective synthesis of C3 alkylated and arylated benzothiophenes. Nat. Commun. 2017, 8, 14801. (r) Shang, L.; Chang, Y.; Luo, F.; He, J.-N.; Huang, X.; Zhang, L.; Kong, L.; Li, K.; Peng, B. Redoxneutral α-arylation of alkyl nitriles with aryl sulfoxides: A rapid electrophilic rearrangement. J. Am. Chem. Soc. 2017, 139, 4211. (s) Kaldre, D.; Klose, I.; Maulide, N. Sterodivergent synthesis of 1,4dicarbonyls by traceless charge-accelerated sulfonium rearrangement. Science 2018, 361, 664. (t) Š iaučiulis, M.; Sapmaz, S.; Pulis, A. P.; Procter, D. J. Dual vicinal functionalisation of heterocycles via an interrupted Pummerer coupling/[3,3]-sigmatropic rearrangement cascade. Chem. Sci. 2018, 9, 754. (u) He, Z.; Shrives, H. J.; Fernández-Salas, J. A.; Abengózar, A.; Neufeld, J.; Yang, K.; Pulis, A. P.; Procter, D. J. Synthesis of C2 Substituted Benzothiophenes via an Interrupted Pummerer/[3,3]-Sigmatropic/1,2-Migration Cascade of Benzothiophene S-Oxides. Angew. Chem., Int. Ed. 2018, 57, 5759. (v) Aukland, M. H.; Talbot, F. J. T.; Fernández-Salas, J. A.; Ball, M.; Pulis, A. P.; Procter, D. J. An Interrupted Pummerer/Nickel-Catalysed Cross-Coupling Sequence. Angew. Chem., Int. Ed. 2018, 57, 9785. (w) Zhang, Z.; Luo, Y.; Du, H.; Xu, J.; Li, P. Synthesis of αheterosubstituted ketones through sulfur mediated difunctionalization of internal alkynes. Chem. Sci. 2019, 10, 5156. (12) For reviews, see: (a) Gibson, D. H.; DePuy, C. H. Cyclopropanol chemistry. Chem. Rev. 1974, 74, 605. (b) Kulinkovich, O. G. The chemistry of cyclopropanols. Chem. Rev. 2003, 103, 2597. (c) Mack, D. J.; Njardarson, J. T. Recent advances in the metalcatalyzed ring expansions of three-and four-membered rings. ACS Catal. 2013, 3, 272. (d) Nikolaev, A.; Orellana, A. Transition-metalcatalyzed C−C and C−X bond-forming reactions using cyclopropanols. Synthesis 2016, 48, 1741. (e) Fumagalli, G.; Stanton, S.; Bower, J. F. Recent methodologies that Exploit C−C single-bond cleavage of strained ring systems by transition metal complexes. Chem. Rev. 2017, 117, 9404. (f) Ebner, C.; Carreira, E. M. Cyclopropanation strategies in recent total syntheses. Chem. Rev. 2017, 117, 11651. (13) For selected recent applications, see: (a) Parida, B. B.; Das, P. P.; Niocel, M.; Cha, J. K. C−acylation of cyclopropanols: preparation of functionalized 1,4-diketones. Org. Lett. 2013, 15, 1780. (b) Cheng, K.; Walsh, P. J. Arylation of aldehyde homoenolates with aryl bromides. Org. Lett. 2013, 15, 2298. (c) Li, Y.; Ye, Z.; Bellman, T. M.; Chi, T.; Dai, M. Efficient synthesis of β-CF3/SCF3-substituted carbonyls via copper-catalyzed Electrophilic ring-opening crosscoupling of cyclopropanols. Org. Lett. 2015, 17, 2186. (d) Ye, Z.; Dai, M. An Umpolung strategy for the synthesis of β-aminoketones via copper-catalyzed electrophilic amination of cyclopropanols. Org. Lett. 2015, 17, 2190. (e) Ye, Z.; Gettys, K. E.; Shen, X.; Dai, M. Copper-catalyzed cyclopropanol ring opening Csp3−Csp3 cross5604
DOI: 10.1021/acs.orglett.9b01908 Org. Lett. 2019, 21, 5600−5605
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Organic Letters Imidazole Derivative. Org. Lett. 2005, 7, 929. (d) Feldman, K. S.; Vidulova, D. B.; Karatjas, A. G. Extending Pummerer Reaction Chemistry. Development of a Strategy for the Regio- and Stereoselective Oxidative Cyclization of 3-(ω-Nucleophile)-Tethered Indoles. J. Org. Chem. 2005, 70, 6429. (e) Feldman, K. S.; Karatjas, A. G. Extending Pummerer Reaction Chemistry. Asymmetric Synthesis of Spirocyclic Oxindoles via Chiral Indole-2-sulfoxides. Org. Lett. 2006, 8, 4137. (f) Feldman, K. S.; Fodor, M. D. Extending Pummerer Reaction Chemistry: (±)-Dibromoagelaspongin Synthesis and Related Studies. J. Org. Chem. 2009, 74, 3449.
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DOI: 10.1021/acs.orglett.9b01908 Org. Lett. 2019, 21, 5600−5605
