Catalytic enantioselective conjugate addition of metalated heteroaryl nucleophiles

• Main Author: Abbott, Lily Katherine
• Format: Others
• Language: English
• Published: 2010
• Subjects: Enantioselective conjugate addition; Heteroaryl zinc reagent; Titanate; Rhodium catalysis
• Online Access: http://hdl.handle.net/2152/ETD-UT-2010-05-1466

This report details the discovery of a method for rhodium catalyzed asymmetric conjugate additions of heteroaryl nucleophiles to α,β-unsaturated carbonyl compounds. This work has successfully employed heteraryl titanates in enantioselective conjugate addition to α,β-unsaturated carbonyl compounds for the first time. Moreover, the utility of benzofuranyl, benzothiophenyl, and pyrrolo zinc reagents has been exemplified in enantioselective conjugate additions. We have found that the precatalyst [Rh(COD)acac]/OMeBIPHEP is broadly effective for enantioselective conjugate additions. Each heterocycle tested exhibited unique reactivity with respect to both conversion and enantioselectivity; reactivities of heteroaryl zinc reagents and heteroaryl titanates in enantioselective conjugate additions to α,β-unsaturated carbonyl compounds are sometimes complementary. Efforts directed towards the development of a method for rhodium-free enantioselective conjugate addition of furan to α,β-unsaturated carbonyl compounds are also described. === text