Nucleophilic Aromatic Substitution by Organoaluminum Reagents

NaOH a granular white tetraethylammonium salt is formed, which is soluble in both water and ... Application to the Synthesis of Indoles. Junya Fujiwar...
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J . Am. Chem. SOC.1983, 105, 7177-7179 Scheme I. Proposed Mechanism of Hydrolysis of W(CCMe,)(CH,CMvle,),

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thanks the Bantrell Foundation for a postdoctoral fellowship, and S.F.P. thanks the Dow Central Research Department for a predoctoral fellowship. We also thank Dr. Catherine Costello and Dr. Henrianna Pang for obtaining FD mass spectra (NIH Grant RR317 to K. Biemann). Registry No. 1, 87615-70-1; 2, 87615-69-8; W(CCMe3)(CH2CMe3)3, 68490-69-7; W20S(CH,CMe3)4(CD2CMe3)2, 87615-71-2; W ( 0 ) (CH2CMe3)3C1, 75846-05-8; W(CCMe,)(OCMe3)3, 78234-36-3; NEt,OH, 77-98-5.

Nucleophilic Aromatic Substitution by Organoaluminum Reagents. Application to the Synthesis of Indoles insoluble and as yet uncharacterized white powder. However, if the water contains 1 equiv of NaOH, a colorless solution is obtained. If tetraethylammonium hydroxide is used instead of NaOH a granular white tetraethylammonium salt is formed, which is soluble in both water and dichloromethane. IR, NMR, and FD mass spectral data all suggest that this species is [NEt,][W03(CH2CMe3)](2; eq 2).’ This complex does not darken W(CCMe3)(0CMe3)3+ N E t 4 0 H [NEt41 [W03(CHzCMe3)1 (2) 2

Junya Fujiwara, Yoshimi Fukutani, Hiromi Sano, Keiji Maruoka, and Hisashi Yamamoto*

Department of Applied Chemistry, Nagoya University Chikusa, Nagoya 464, Japan

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at increased temperatures and has a melting point of 164 OC in air. It is stable in water at pH 7, but appears to be more readily hydrolyzed by aqueous acid or base than 1. The organic product of hydrolysis of 2 by 1 N NaOH at 25 “ C overnight was shown to be neopentane (1.0 (*0.1) equiv in ether layer by GLC). W203(CH2CMe3)6 and [W03(CH2CMe3)]-can be added to the short list of do complexes containing only oxo and alkyl ligands, Le., V(0)(CH2SiMe3)3,8Re02Me3,9Re03Me,10and alkyl molybdates such as [Mo03Me]- (observed in solution”). Preliminary results suggest that other tungsten(V1) alkylidyne complexes do not hydrolyze in as controlled a fashion as neopentylidyne complexes. For example, neither W(CEt)(CH2CMe3)312 nor W(CEt)(OCMe3)313hydrolyzes smoothly to give compounds analogous to 1 and 2, respectively. However, W(CPh)(OCMe3)314 does appear to yield [Et,N] [W03(CH2Ph)]. The most surprising result is that 1 and 2 are so stable thermally, as well as to hydrolysis. This is likely to be a general property of such compounds since the V8 and Re9310complexes above are also reportedly stable to air and water, and [Mo03R]reportedly]’ hydrolyzes relatively slowly at pH 7. We are attempting to prepare 1 and 2 by more direct routes that do not involve neopentylidyne precursors. Preparation of analogous compounds containing other hydrocarbon ligands and analogous compounds containing molybdenum has also been undertaken. We are especially interested in reactions of the alkyl ligand that are relevant to catalysis by molybdenum or tungsten oxides.

Acknowledgment. R.R.S. thanks the National Science Foundation for supporting this research (Grant C H E 81-21282), I.J. (7) ‘H NMR (CDT12) 6 3.35 (9, 8, NCH~CHI),1.68 (s, 2, JHw= 15 Hz, CH2CMe3),1.34 (t, 12, NCH2CH3), 1.02 (s, 9, CH2CMe3);I3C(lH)NMR (CDXI,) 6 54.67 (CHXMe,), 52.84 (NCHXH,), 33.60 (CMe,), 31.68 (CM-e3);7.82 ( N C H 2 M 3 ) ;IR (Nujol) 980 (vi), 925 (vs), 800 (s), 690 (vs), 655 cm-’ (vs). The ([NEt4]2[W03(CH2CMe3)])+ ion was observed in the FD mass spectrum. (8) Mowat, W.; Shortland, A,; Yagupsky, G.; Hill, N . J.; Yagupsky, M.; Wilkinson, G. J . Chem. SOC.,Dalton Trans. 1972, 532. (9) Mertis, K.; Wilkinson, G. J . Chem. SOC.,Dalton Trans. 1976, 1488. (10) Beattie, I. R.; Jones, P. L. Inorg. Chem. 1979, 18, 2318. (1 1) Schrauzer, G. N.; Hughes, L.; Strumpach, N. Z . Naturforsch., B 1982, 376, 380. (12) This complex is a yellow oil prepared by reacting W(CEt)(OCMe3),13 with 3 equiv of CIMgCH2CMe3followed by a 40 “C sublimation at