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Palladium-Catalyzed Asymmetric Cycloisomerization of Enynes with Chiral Sulfinyl Functionality

钯催化具有手性亚磺酰基官能团的烯炔的不对称环异构化

基本信息

批准号：
09672153
负责人：
HIROI Kunio
金额：
$ 1.86万
依托单位：
Tohoku Pharmaceutical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

A transition metal-catalyzed carbon-carbon bond formation reaction is one of the most advantageous method for the stereo- and enantioselective construction of cyclic compounds. In order to develop a new useful methodology for the asymmetric synthesis of five-membered compounds, we have studied palladium-catalyzed asymmetric cycloisomerization of readily available 1,6-enyes with chiral phosphine ligands or chiral sulfinyl functionality.1. The palladium-catalyzed asymmetric cycloisomerizations of 1 , 6-enyes with chiral phosphine ligands produced optically active cyclopentane derivative with rather high enantioselectivity. The use of a chiral ferrocenyl phosphine as a ligand provided highest enantioselectivity.2. The palladium-catalyzed reactions of l, 6-enyes bearing chiral sulfinyl groups at the appropriate sites in the olefinic parts gave cycized compounds, 1,4-dienes and 1,3-dienes with rather high enantiomeric excess. It should be noted that the stereoselectivity, production ratios of the 1,4-dienes to the 1,3-dienes, was dependent upon the steric envilonment around the sulfinyl groups. The plausible mechanis is proposed to rationalize the stereochemical results.3. The palladium-catalyzed reactions of 1,6-enyes bearing chiral sulfinyl groups at the sites in the acetylenic parts produced exclusively 1,4-dienes with rather low e.e.. The steric results are rationalized by the formation of palladacycic intermediates.4. Introduction of carboxyl functions into l, 6-enye substrates enhanced enantiocontrol, presum ably due to the conformational fixation of the intermediary palladacycles.

过渡金属催化的碳-碳键形成反应是立体和对映选择性构造环状化合物最有利的方法之一。为了开发一种新的五元化合物的不对称合成方法，我们研究了钯催化的手性膦配体或手性亚砜基不对称环异构化反应。钯催化1,6 -烯基与手性膦配体的不对称环异构化反应生成了具有较高对映选择性的光学活性环戊烷衍生物。使用手性二茂铁基膦作为配体提供了最高的对映选择性。在钯的催化下，1,6 -enyes在烯烃部分的适当位置上携带手性亚砜基，得到环化化合物1,4-二烯和1,3-二烯，对映体过量相当高。值得注意的是，立体选择性，即1,4-二烯与1,3-二烯的生成比，取决于亚砜基周围的空间环境。提出了一种合理的机制来合理化立体化学结果。在钯的催化下，1,6-烯类化合物在乙炔部分的位置上带有手性亚砜基，只产生具有较低e值的1,4-二烯。空间构型的结果被钯基中间体的形成所合理化。在1,6 -烯基底物中引入羧基功能增强了对映体控制，可能是由于中间环的构象固定。