1,2-Silyl-migrative cyclization of vinylsilanes bearing an amino group.
In the presence of an acid catalyst, alpha-alkyl-substituted (Z)-vinylsilanes 1, bearing a tosylamino group, were smoothly cyclized to trans-2-alkyl-3-silylpiperidines 2 (1,2-silyl-migration products) and (2R*, 1'S*)-2-(1'-silylalkyl)pyrrolidines 3. The elaboration of the reaction conditions enabled the selective preparation of each cyclized product. The acid-catalyzed cyclization of (Z)-vinylsilane 5, whose methylene tether is shorter than that of 1 by one carbon, formed only the 1,2-silyl-migration product 6 with high trans-selectivity. These cyclizations were found to proceed in a stereospecific manner.
Miura
Katsukiyo
K
Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
Takahashi
Tatsuyuki
T
Hondo
Takeshi
T
Hosomi
Akira
A