Effects of Silyl Substituents on the Palladium-Catalyzed Asymmetric Synthesis of Axially Chiral (Allenylmethyl)silanes and Their SE2′ Chirality Transfer Reactions
作者:Masamichi Ogasawara、Yonghui Ge、Atsushi Okada、Tamotsu Takahashi
DOI:10.1002/ejoc.201101634
日期:2012.3
A series of axially chiral 4-substituted-1-silyl-2,3-butadienes [(allenylmethyl)silanes] were synthesized from 3-bromo-5-silylpenta-1,3-dienes by a Pd-catalyzed asymmetric reaction with a soft nucleophile. The optically active (allenylmethyl)silanes react with an acetal in the presence of TiCl4 to give the enantiomerically enriched 1,3-diene derivatives through an SE2′ pathway. Effects of the silyl
一系列轴向手性 4-取代-1-甲硅烷基-2,3-丁二烯 [(allenylmethyl) 硅烷] 是由 3-bromo-5-silylpenta-1,3-二烯通过 Pd 催化的不对称反应合成的。亲核试剂。旋光性(烯丙基甲基)硅烷在 TiCl4 存在下与缩醛反应,通过 SE2' 途径得到富含对映异构体的 1,3-二烯衍生物。研究了甲硅烷基对不对称丙二烯合成和随后的SE2'手性转移反应的对映选择性的影响。发现随着 3-bromo-5-silylpenta-1,3-二烯中甲硅烷基的空间体积从 -SiMe3 增加到 -SiiPr3,两种对映选择性过程的对映选择性也提高了。