Diastereoselective [2,3]-sigmatropic rearrangements of lithium N-benzyl-O-allylhydroxylamides bearing a stereogenic centre adjacent to the migration terminus
作者:Steven D. Bull、Stephen G. Davies、Sara Hernández Domíngez、Simon Jones、Anne J. Price、Thomas G. R. Sellers、Andrew D. Smith
DOI:10.1039/b207069n
日期:——
3]-sigmatropic rearrangements of lithium N-benzyl-O-allylhydroxylamides bearing a stereogenic centre adjacent to the migration terminus are examined. (E)-N-Benzyl-O-(4-phenylpent-2-enyl)hydroxylamine rearranges in 30% de to afford syn-(3RS,4RS)-3-(N-benzyl-N-hydroxy)-4-phenylpent-1-ene as the major diastereoisomer, consistent with the rearrangement proceeding under moderate steric control. Rearrangements of both
研究了带有邻近迁移末端的立体中心的N-苄基-O-烯丙基羟基锂锂的非对映选择性[2,3]-σ重排。(E)-N-苄基-O-(4-苯基戊-2-烯基)羟胺在30%的重排去,得到顺式- (3- RS,4个RS)-3-(ñ -苄基- ñ -羟基)-4-苯基戊-1-烯作为主要非对映体,具有适度的空间位阻控制下重新排列程序相一致。锂(E)-和(Z)-N-苄基-O-(4-甲氧基-4-苯基丁-2-烯基)羟基叠氮化物的重排提供了syn-(1 RS,2 RS)-1-苯基-1-分别≥90%和88%的甲氧基-3-(N-苄基氨基)丁-3-烯,与在螯合控制下进行的这些重排一致。