Soderquist, Hassner
1 Acyl Derivatives of
Silicon, G e r m a n i u m , a n d Tin
Supplementary Material Available: A table of observed and calculated structure factors (5 pages). Ordering information is given on any current masthead page.
References and Notes (1) Eakens, J. D.; Humphreys, D. G.; Mellish, C. E. J. Chem. SOC. 1963, 6012. (2) (a) Cotton, F. A,; Bratton, K. W. J. Am. Chem. SOC. 1965, 87, 921. (b) Bratton, W. K.; Cotton, F. A. Inorg. Chem. 1970, 9, 789. (c)Cotton, F. A,; Shive, L. W. bid. 1975, 14, 2032. (3) Cotton. F. A,; Pederson, E. Inorg. Chem. 1975, 14, 383. (4) Cotton, F. A,; Fanwick, P. E.; Gage, L. D.; Kalbacher, 6.J.; Martin, D. S. J. Am. Chem. SOC.1977, 99,5642. (5) Cotton, F. A,; Kalbacher, B. J. Inorg. Chem. 1977, 16, 2386. (6) Schwochau, K.; Hedwig, K.; Schenk, H. J.; Greis, 0. Inorg. Nucl. Chem. Len. 1977, 13, 77.
1511
(7) Cotton, F. A.; Davison, A,; Day, V. W.; Gage, L. D.; Trop, H. S . Inorg. Chem. 1979, 18, 3024. (8) Cotton, F. A.; Gage, L. D. Nouveau J. Chim. 1977, 1, 441. (9) Collins, D. M.; Cotton, F. A,; Gage, L. D. Inorg. Chem. 1979, 78,1712. (IO) Cotton, F. A.; Gage, L. D. Inorg. Chem. 1979, 18, 1716. (1 1) Procedures for data collection and data reduction with the CAD-4 diffractometer have been described earlier: Bino, A.; Cotton, F. A,; Fanwick, P. E. Inorg. Chem. 1979, 18, 3558. (12) All computing to solve and refine the structure was carried out on a PDP 11/45 computer at the Molecular Structure Corp., College Station, Tex., using the Enraf-Nonius structure determination package with some local modifications. (13) Cotton, F. A.; Fanwick, P. E. J. Am. Chem. SOC. 1979, 101, 5252. (14) Fanwick, P. E.; Martin, D. S.; Cotton, F. A.; Webb, T. R. Inorg. Chem. 1977, 76,2103. (15) Martin, D. S.;Newman, R. A.; Fanwick, P. E. Inorg. Chem. 1979, 18, 2511.
Unsaturated Acyl Derivatives of Silicon, Germanium, and Tin from Metalated Enol Ethers2a John A. Soderquistla and Alfred Hassner*lb Contribution from the Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13901. Received J u l y 2, I979
Abstract: The preparation of I-lithio derivatives of some conjugated vinyl ethers is described. Reaction of these compounds with the chlorotrimethyl derivatives of silicon, germanium, and tin gives the corresponding metallovinyl ethers in 50-80% yield. At least in the case of silicon these reactions proceed with retention of stereochemistry. The silyl compounds undergo Z * E photoisomerization. Hydrolysis of the ethers in aqueous acetone gives the corresponding acylmetallanes in 60-75% yield. The metalation and hydrolysis reactions are examined in some detail. The spectral properties of these novel unsaturated acylmetallanes are presented and discussed.
Introduction S t u d i e s in our laboratory have revealed t h a t l-trimethylsilylacetylenes c a n be converted to t h e corresponding a-silaketones (acylsilanes) using a hydroboration/oxidation sequence.2b From t h e enyne 1, it was possible to prepare t h e first exa m p l e of a n acrylic a , P - u n s a t u r a t e d acylsilane (3) since t h e oxidation of the vinylboronate ( 2 ) is accompanied by isomerization of t h e double bond into conjugation (eq 1). In spite of
= -%Me,
1. BHCI,~OEt,/BCI,
2. MeOH/Me,N
1
2
0
-
+
Results and Discussion Synthesis and Photochemistry of Metalated Enol Ethers. W h e n trans-l-methoxy-l,3-butadienewas metalated using 1 equiv of tert-butyllithium a n d the resulting 1-1ithiated compound ( 5 ) was treated with the chlorotrimethyl derivatives of silicon, germanium, and tin, the corresponding adducts (6) (eq 2) were isolated in good yields.
SiMe,
0 +-NMe2.2H,0
lithiated I-methoxybutadiene can be used as a crotonyl anion e q ~ i v a l e n t Owing .~ to the exceptionally mild conditions required to hydrolyze vinyl ethers, a n approach to a , p - u n s a t u rated acylmetallanes based on such compounds seemed particularly attractive. Therefore, we undertook a n investigation of the metalation of several representative vinyl ethers and their conversion to acylmetallanes.
>-K
OMe
/
OMe
LiBu-t
/
SiMe,
3 repeated attempts, we were unable to extend this method to t h e preparation of the corresponding germanium and tin ketones. U n d e r our conditions, the hydroboration step failed to give the desired adducts, presumably owing to the strong Lewis acid nature of the reactants. Therefore, we chose to investigate other routes to 3, which could accommodate not only a variety of enone moieties, but also germanium a n d tin substitution. To date, the most convenient a n d general methods for the preparation of acyl derivatives of silicon and germanium involve the use of masked acyl anion e q ~ i v a l e n t s ,including ~ the dithiane m e t h ~ d Unfortunately, .~ this method fails in the hydrolysis step for t h e tin case.4 M o r e recently, Baldwin and co-workers have reported that
0002-7863/80/ 1502- I577$0 I .OO/O
Me ,MCI
H
OMe MMe,
6a, M = Si b, M = Ge c, M = Sn
(
