恶唑硼烷酮催化的无环α,β-不饱和酮的对映选择性狄尔斯-阿尔德反应

Oxazaborolidinone-catalyzed enantioselective Diels-Alder reaction of acyclic alpha,beta-unsaturated ketones.

作者信息

Singh Ram Shanker, Adachi Shinya, Tanaka Fumi, Yamauchi Toyonao, Inui Chieko, Harada Toshiro

机构信息

Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.

出版信息

J Org Chem. 2008 Jan 4;73(1):212-8. doi: 10.1021/jo702043g. Epub 2007 Dec 6.

DOI:10.1021/jo702043g

PMID:18052389

Abstract

allo-Threonine-derived O-acyl-B-phenyl-oxazaborolidinones are demonstrated to be powerful and highly enantioselective Lewis acid catalysts for the Diels-Alder reaction of simple acyclic enone dienophiles, expanding the scope of ketone dienophiles and dienes. With 10 to 20 mol % of catalyst, the Diels-Alder adducts are obtained in 76-98% ee with high endo-selectivity. The catalyst exhibits high activity for the reaction with the less reactive beta-substituted dienophiles and the less reactive 1,3-cycohexadiene and 1,3-butadiene derivatives. The application of the catalysts to the Diels-Alder reaction of furan is also described.

摘要

源自别苏氨酸的O-酰基-β-苯基恶唑硼烷酮被证明是用于简单无环烯酮亲双烯体的狄尔斯-阿尔德反应的高效且高度对映选择性的路易斯酸催化剂，拓展了酮亲双烯体和二烯的范围。使用10%至20%摩尔的催化剂，可获得对映体过量值为76 - 98%且具有高内型选择性的狄尔斯-阿尔德加合物。该催化剂对于与反应活性较低的β-取代亲双烯体以及反应活性较低的1,3-环己二烯和1,3-丁二烯衍生物的反应表现出高活性。还描述了这些催化剂在呋喃的狄尔斯-阿尔德反应中的应用。