Palladium-Catalyzed Asymmetric Synthesis of Axially Chiral (Allenylmethyl)silanes and Chirality Transfer to Stereogenic Carbon Centers in S<sub>E</sub>‘ Reactions
作者:Masamichi Ogasawara、Kazuhito Ueyama、Takashi Nagano、Yoshiyuki Mizuhata、Tamio Hayashi
DOI:10.1021/ol027291w
日期:2003.1.1
[reaction: see text] Novel stereoselective reactions of 4-substituted-1-trimethylsilyl-2,3-butadienes ((allenylmethyl)silanes) were developed. The axially chiral (allenylmethyl)silanes were prepared from (3-bromopenta-2,4-dienyl)trimethylsilane by a Pd-catalyzed asymmetric reaction with soft nucleophiles with up to 88% enantioselectivity. The (allenylmethyl)silanes reacted with acetals in the presence
[反应:见正文]开发了4-取代的-1-三甲基甲硅烷基-2,3-丁二烯((烯丙基甲基)硅烷)的新型立体选择性反应。轴向手性(烯丙基甲基)硅烷是由(3-溴戊-2,4-二烯基)三甲基硅烷通过Pd催化的不对称反应与柔软的亲核试剂以高达88%的对映选择性制备的。(烯丙基甲基)硅烷在TiCl(4)助催化剂的存在下与缩醛反应,通过S(E)'途径生成1,3-二烯衍生物。1,3-二烯基产物仅具有(E)-几何形状,并且在S(E)'反应中观察到高达88%()()手性从轴向手性亚烯基转移到中心手性1,3-二烯。