Studies into the Diels–Alder reactions of 5-trimethylsilylthebaine
作者:Weibin Chen、Gary D. Strahan、Damon A. Parrish、Jeffrey R. Deschamps、Andrew Coop
DOI:10.1016/j.tetlet.2004.11.010
日期:2005.1
The introduction of a 5-trimethylsilyl group on the least hindered face of the diene thebaine was anticipated to favor attack by dienophiles front the alternate face, but only gave rise to a rearrangement product when treated with 3-butene-2-one at 110degreesC. Reaction with the more reactive benzoquinone at lower temperature gave rise to a very slow reaction from the same face as the silyl group, indicating that a trimethylsilyl group does not sufficiently hinder this face to achieve reaction at the other face. (C) 2004 Elsevier Ltd. All rights reserved.
Rearrangement of 5-Trimethylsilylthebaine on Treatment with L-Selectride: An Efficient Synthesis of (+)-Bractazonine
作者:Weibin Chen、Huifang Wu、Denzil Bernard、Matthew D. Metcalf、Jeffrey R. Deschamps、Judith L. Flippen-Anderson、Alexander D. MacKerell,、Andrew Coop
DOI:10.1021/jo020704m
日期:2003.3.1
rise to a rearrangement to 10-trimethylsilylbractazonine through migration of the phenyl group, whereas treatment of thebaine with strong Lewis acids is known to lead to a similar rearrangement through migration of the alkyl bridge to give, after reduction, (+)-neodihydrothebaine. It is suggested that the rearrangement of the alkyl group of thebaine is favored due to the formation of a tertiary benzylic