An Intramolecular Titanium-Catalyzed Asymmetric Pauson−Khand Type Reaction<sup>1</sup>
作者:Frederick A. Hicks、Stephen L. Buchwald
DOI:10.1021/ja990683m
日期:1999.8.1
The development of the first catalytic asymmetric Pauson−Khand type cyclization of enynes is described. The active catalyst, (S,S)-(EBTHI)Ti(CO)2 (1), is generated in situ from (S,S)-(EBTHI)TiMe2 (2). A variety of 1,6-enynes can be converted to the corresponding cyclopentenones in high yield (70−94%) with excellent ee's (87−96%). Limitations of the catalyst with respect to substrate structure are discussed
描述了烯炔的第一个催化不对称 Pauson-Khand 型环化的发展。活性催化剂 (S,S)-(EBTHI)Ti(CO)2 (1) 是由 (S,S)-(EBTHI)TiMe2 (2) 原位生成的。各种 1,6-烯炔可以以高产率 (70-94%) 转化为相应的环戊烯酮,具有出色的 ee (87-96%)。讨论了催化剂在基材结构方面的局限性。几种烯酮产品的绝对构型已经确定,这些分配代表了与初始报告中分配的逆转。提出了该催化剂的对映选择性的意义和水平的基本原理。