DirectcatalyticasymmetricMannich-typereactions of gamma-butenolides are described. A chiral Lewis acid/amine base/Bronsted acid combination was used to catalyze a gamma-addition of gamma-butenolides to N-diphenylphosphinoyl imines, affording the products in up to >99% yield, anti/syn = >97:3, and 84% ee. The use of a catalytic amount of TfOH in addition to La(OTf)3/Me-PyBox/TMEDA was important
描述了γ-丁烯内酯的直接催化不对称曼尼希型反应。手性路易斯酸/胺碱/布朗斯台德酸的组合用于催化γ-丁烯内酯向N-二苯基膦酰基亚胺的γ加成反应,从而使产物收率最高> 99%,反/ syn => 97:3,并且84%ee。除La(OTf)3 / Me-PyBox / TMEDA外,还使用催化量的TfOH对于提高收率和立体选择性很重要。
Axially chiral phosphine–oxazoline ligands in silver(I)-catalyzed asymmetric Mannich reaction of N-Boc aldimines with trimethylsiloxyfuran
作者:Qian-Yi Zhao、Min Shi
DOI:10.1016/j.tet.2011.03.046
日期:2011.5
Axiallychiralphosphine–oxazolineligand L6 was found to be a fairly effective chiralligand in silver(I)-catalyzed asymmetricMannichreaction of N-Boc aldimines with trimethylsiloxyfuran to give the corresponding adducts in up to 97% yield, 7:1 dr and 86% ee (major diastereoisomer).