Stereoselective Conjugate Addition of Alkyl Groups to ( S )-4-( tert -Butyldimethylsilyloxy)-2-cyclopentenone Derivatives
作者:Takayuki Yakura、Kenji Tanaka、Tomoko Kitano、Jun'ichi Uenishi、Masazumi Ikeda
DOI:10.1016/s0040-4020(00)00686-4
日期:2000.9
Reaction of (S)-2-benzenesulfonyl-4-(tert-butyldimethylsilyloxy)-2-cyclopentenone (2) and a 2-methoxycarbonyl congener (3) with R2CuLi or RMgBr-CuI stereoselectively gave (2S,3R,4S)-3-alkyl-2-benzenesulfonyl-4-(tert-butyldimethylsilyloxy)cyclopentanone (4) and its (2S,3S,4S)-2-methoxycarbonyl derivative (5) as a major diastereoisomer. On the other hand, reaction with R3Al in toluene exclusively gave the corresponding 3,4-cis-adducts 6 and 7. (C) 2000 Elsevier Science Ltd. All rights reserved.