Development of Acyl and Silyl Group Transfer Reactions of Ketene Acetal Derivatives Utilizing Enol-Keto Transformation and Their Applications to the Synthesis of Natural Products

Abstract

The title acyl or silyl group transfer reactions under neutral or nearly neutral conditions can be classified into the following two types: i) simple acyl/proton or silyl/proton exchange reactions of H-acidic materials such as amines, alcohols, carboxylic acids, mercaptans, phenols, and imides accompanied by volatile alkyl acetates (type I reaction), and ii) aldol or Michael additions of alkyl acetate anions to carbonyl compounds accompanied by a silyl group transfer on the oxygen atom of carbonyl groups (type II reaction). Synthetic reagents utilizing these reactions, e. g., alkoxycarbonylation, Semmler-Wolff aromatization, silylation, silylenation, Pummerer-type rearrangement, acid anhydride or amide formation are discussed. Applications of these reagents or reactions to the synthesis of biologically important natural products, methyl jasmonates, 2-deoxy-D (and L)-riboses, and anthracyclines are also described.