Enantioselective [2,3]-Wittig Rearrangement <i>via</i> Sparteine-Mediated Lateral Metalation of <i>N,N</i>-Dialkyl-<i>o</i>-allyloxymethylbenzamides and <i>o</i>-Substituted Benzyl Prenyl Ethers
作者:Takeshi Kawasaki、Tetsutaro Kimachi
DOI:10.1055/s-1998-1978
日期:1998.12
The (-)-sparteine-mediated enantioselective [2,3]-Wittig rearrangement of N,N-dialkyl-o-allyloxymethylbenzamides and o-substituted benzyl prenyl ethers has been investigated. With N,N-diethyl-o-allyloxymethylbenzamide, enantiomeric excess up to 60% was observed in pentane. These results suggest that the carbamoyl group can effectively assist the transfer of stereoinformation by coordinating with the (-)-sparteine-n-BuLi complex. Other functional groups (OMe, OCONR2, OMOM, F) were impotent to the enantiodifferentiation of this rearrangement.
已研究了(-)-sparteine介导的N,N-二烷基-o-烯丙氧基甲基苯酰胺和o-取代苄基普尼醚的对映选择性[2,3]-Wittig重排。使用N,N-二乙基-o-烯丙氧基甲基苯酰胺时,在戊烷中观察到了高达60%的对映体过量。这些结果表明,氨基羧基可以通过与(-)-sparteine-n-BuLi复合物的配位有效地辅助立体信息的传递。其他功能团(OMe、OCONR2、OMOM、F)对该重排的对映体分化无效。