Asymmetric Synthesis of α-Substituted Aldehydes by Pd-Catalyzed Asymmetric Allylic Alkylation−Alkene Isomerization−Claisen Rearrangement
作者:Barry M. Trost、Ting Zhang
DOI:10.1021/ol0624878
日期:2006.12.1
Enantiospecific aliphatic Claisen rearrangement was realized with generally high chirality transfer. The requisite substrates were synthesized via Pd-catalyzed asymmetric allylic alkylation (AAA) from easily obtained starting materials. After protection, the resultant bisallyl ethers underwent olefin isomerization and in situ Claisen rearrangement (ICR) to generate alpha-chiral aldehydes. Remarkable chemoselectivity
[结构:见正文]通过通常的高手性转移实现了对映体特异性的脂族克莱森重排。必需的底物是通过Pd催化的不对称烯丙基烷基化反应(AAA)从容易获得的起始原料合成的。保护后,将所得的双烯丙基醚进行烯烃异构化和原位克莱森重排(ICR),以产生α-手性醛。在烯烃异构化步骤中观察到显着的化学选择性。应用该方法完成了Commununiol A的不对称合成。