Caumul, Prakashanand; (2002) Synthesis of novel surfactants and their use in asymetric catalysis. Doctoral thesis (Ph.D), UCL (University College London).

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Abstract

Micelles can affect the rate, stereo-, regio- and enantioselectivity of organic reactions. ¹²³ This project investigates the synthesis and use of several novel surfactants as micellar catalysts in aqueous and organic media. Previous work within the group has involved the synthesis of surfactants derived from (1S,2R)-norephedrine giving particularly good yields and selectivities in the diethyl zinc addition reactions. ⁴ This thesis is comprised of seven chapters. Initially chapter one reviews the background literature covering: (i) The properties and applications of surfactants. (ii) Previous literature on the addition of diethyl zinc to a range of aldehydes using various chiral catalysts. (iii) Literature on the use of organic reactions in aqueous media. Chapter two describes the synthesis of surfactants derived from different analogues:- S-tyrosine, S-proline, oxazolo pyridinone, and the alkaloids hydroquinidine and cinchonine. The Critical Micelle Concentration (CMC) and Reverse Critical Micelle Concentration (RCMC) analysis of these surfactants are outlined in chapter three using dye solubilisation techniques. Chapters four to six describe the use of these surfactants as catalysts for a number of asymmetric reactions including diethylzinc reactions with various aldehydes. Then use of the catalysts in Michael addition reactions are presented. These reactions are carried out in water. In particular, the reaction between diethyl malonate and cyclopentenone is studied. In addition the use of an -substituted cyclopentenone is described and the reaction selectivities rationalised. The Baylis-Hillman reactions are also investigated in water using a range of activated alkenes and aldehydes and the selectivities and yields obtained are presented and rationalised. Improved yields were achieved when using acidified water. In the final chapter, the experimental section, all experimental procedures are given together with full compound characterisation.

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