Synlett 2004(5): 0749-0760  
DOI: 10.1055/s-2004-817779
ACCOUNT
© Georg Thieme Verlag Stuttgart · New York

Development of the First Practical Catalyst for the Asymmetric Addition of Alkyl- and Arylzinc Reagents to Ketones

Juan M. Betancort, Celina García, Patrick J. Walsh*
P. Roy and Diane T. Vagelos Laboratories, University of Pennsylvania, Department of Chemistry, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323
Fax: 215 573 6743; e-Mail: pwalsh@sas.upenn.edu;
Further Information

Publication History

Received 28 October 2004
Publication Date:
17 February 2004 (online)

Abstract

A long-standing problem in organic synthesis is the catalytic asymmetric addition of alkyl groups to ketones to establish chiral quaternary centers. Such compounds are valuable chiral building blocks that can be further elaborated. In this account, we describe the previously unreported story of the development of the first effective catalyst for the enantioselective addition of dialkyl- and diphenylzinc reagents to ketones. The scope of this reaction is outlined, including a tandem enantioselective addition to cyclic enones/diastereoselective epoxidation protocol that establishes three contiguous stereocenters in a one-pot procedure.

  • 1 Introduction

  • 1.1 Asymmetric Catalysis with Ketones

  • 1.2 Prior Art

  • 2 Our Approach to Catalyst Development

  • 2.1 Asymmetric Alkylation of Ketones

  • 2.2 Generation I Catalysts

  • 2.3 Generation II Catalysts

  • 2.4 Generation III Catalysts - Third Time’s a Charm!

  • 3 Asymmetric Additions to Cyclic Conjugated Enones-­Tandem Asymmetric Alkylation/Epoxidation Reactions

  • 4 Asymmetric Phenylation of Ketones

  • 5 Summary