Iridium-Catalyzed, Regio- and Enantioselective Allylic Substitution with Aromatic and Aliphatic Sulfinates
作者:Mitsuhiro Ueda、John F. Hartwig
DOI:10.1021/ol9023248
日期:2010.1.1
The iridium-catalyzed allylation of sodium sulfinate to form branched allylic sulfones is reported. The reactions between various sodium sulfinates and achiral allylic carbonates occur in good yields, with high selectivity for the branched isomer, and high enantioselectivities (up to 98% ee).
A highlyregio- and enantioselective hydrosulfonylation using commercially available sodium sulfinates is reported, providing the first direct asymmetric rhodium-catalyzed hydrosulfonylation of allenes/alkynes to synthesize chiral allylic sulfones. Ligand screening studies demonstrated the indispensable role of the C1-symmetric P,N-ligand (Rax,S,S)-StackPhim for achieving both high regioselecitivity
据报道,使用市售亚磺酸钠进行高度区域和对映选择性氢磺酰化,提供了第一个直接不对称铑催化的丙二烯/炔烃氢磺酰化,以合成手性烯丙砜。配体筛选研究证明了C 1 -对称 P,N-配体 ( R ax , S , S )-StackPhim 对于实现高区域选择性 (>20:1) 和对映选择性 (高达 97% ee) 的不可或缺的作用。值得注意的是,操作简单的方法和温和的条件允许快速制备具有广泛官能团的手性烯丙基砜。此外,使用叔丁基二甲基甲硅烷氧基甲亚磺酸钠可以在受保护的羟甲基产物的简单转化后集体合成各种手性砜衍生物。
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.
Rhodium-Catalyzed Regio- and Enantioselective Allylic Sulfonylation from Sulfonyl Hydrazides