Stereoselektive Alkylierung an C (α) von Serin, Glycerinsäure, Threonin und Weinsäure über heterocyclische Enolate mit exocyclischer Doppelbindung

D Seebach, JD Aebi, M Gander??Coquoz…

Index: Seebach, Dieter; Aebi, Johannes D.; Gander-Coquoz, Marlyse; Naef, Reto Helvetica Chimica Acta, 1987 , vol. 70, p. 1194 - 1216

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Citation Number: 148

Abstract

The chiral, non-racemic title acids are converted to methyl dioxolane-(cJ 13), oxazoline-(4) and oxazolidinecarboxyiates (cf 9). Deprotonation by Li (i-Pr), N at dry-ice temperature gives solutions of the lithium enolates AD with exocyclic enolate double bonds. These are stable enough with respect to 8-elimination (Scheme I) to be alkylated with or without cosolvents such as HMPA or DMPU. The products are formed in good to excellent yields and, with the ...