报道了铑催化的丙二腈的区域和对映选择性分子间烯丙基化反应,即带有末端和对称内部烯基的掩蔽酰基氰化物(MAC)。Rh I / Josiphos催化体系与随后的一级加合物的氧化降解相结合,可以直接获得α支化,β,γ-不饱和羰基化合物。本方案在烯丙基化步骤中展现出完美的原子经济性,并且具有良好的官能团相容性。此外,使用α-取代的丙二腈可以构建全碳四元中心。
Iridium-Catalyzed Kinetic Asymmetric Transformations of Racemic Allylic Benzoates
作者:Levi M. Stanley、Chen Bai、Mitsuhiro Ueda、John F. Hartwig
DOI:10.1021/ja103779e
日期:2010.7.7
Versatile methods for iridium-catalyzed, kinetic asymmetric substitution of racemic, branched allylic esters are reported. These reactions occur with a variety of aliphatic, aryl, and heteroaryl allylic benzoates to form the corresponding allylic substitution products in high yields (74-96%) with good to excellent enantioselectivity (84-98% ee) with a scope that encompasses a range of anionic carbon and heteroatom nucleophiles. These kinetic asymmetric processes occur with distinct stereochemical courses for racemic aliphatic and aromatic allylic benzoates, and the high reactivity of branched allylic benzoates enables enantioselective allylic substitutions that are slow or poorly selective with linear allylic electrophiles.