Stereoselective synthesis of β-ketoenol triflates under aqueous conditions

ORGN 593

Damian G. Weaver, Process Research, Merck, 466 Devon Park Drive, Wayne, PA 19087-1816, Doug E. Frantz, Process Chemistry, Merck, 466 Devon Park Drive, Wayne, PA 19087-1816, Michael H. Kress, Process Research, Merck Research Laboratories, 466 Devon Park Drive, Mailstop WYN-1, Wayne, PA 19087, and Kristen Hyland, Department of Chemistry, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085.
Traditionally beta-ketoenol triflates have been prepared from beta-ketoesters using amine bases with little or no E/Z selectivity. We have prepared beta-ketoenol triflates from beta-ketoesters under aqueous reaction conditions to selectively synthesize either the Z or E isomer by appropriate choice of base. For example when aqueous LiOH is used the Z isomer can be prepared in ratios of Z: E up to 90:1. Alternatively, the use of aqueous (CH3)4NOH as the base yields the E isomer in E: Z ratios up to 35:1.

 

New Reactions, Methodology, Heterocycles, Aromatics
8:00 PM-10:00 PM, Wednesday, August 25, 2004 Pennsylvania Convention Center -- Hall D, Poster

Division of Organic Chemistry

The 228th ACS National Meeting, in Philadelphia, PA, August 22-26, 2004