Investigating michael addition of aliphatic dicarboxylic acid esters as a synthetic tool

Abstract

The objective of the study was to develop the Michael addition of dicarboxylic acid esters as a tool for synthetic organic chemists. The study has encompasses Michael addition of malonates and succinates to a couple of a,B-unsaturated ketones as represented by the Scheme shown below. The thesis has been divided into four Chapter. In Chapter I an elaborate review on the existing literatures on Michael addition reactions has been presented. It is worth-mentioning that Michael addition reaction is catalyzed by both Lewis acids and bases. A couple of a,B-unsaturated ketones and esters were necessary for the study. All of them have been prepared in the laboratory using well-established methodologies as reported in the literature. Following tables show the ketones and esters which were prepared and reproduced here directly from the body of the thesis. In Chapter III results of lithium hydroxide - mediated Michael addition of dicarboxylic acid esters to a,B-unsaturated ketones are incorporated and discussed. The efficiency of lithium hydroxide as a catalyst in ten different Michael additions of dimethyl malonates to a,B-unsaturated ketones has been examined under three different sets of reaction conditions viz. (i) ambient temperature in methanol, (ii) refluxing temperature in methanol and (iii) microwave irradiation without solvent. Some of the results, as reported in the thesis, are reproduced here in the following table. Best one from among the commonly used solvents, reaction time and quantum of catalyst required for maximum yield have also been examined and reported in the thesis. Unlike the chemistry of dimethyl malonate, the chemistry of dimethyl succinate is not well explored. Some of the result of Michael addition reactions with dimethyl succinate as the Michael donor are shown below. Reaction with other dialkyl malonates and succinates has also been investigated. Iodine is a catalyst of choice in several organic reactions. It is non-toxic and environmentally benign Lewis acid. Iodine catalyzed Michael addition