Solvolytic studies of γ-acetoxyalkylcobaloximes

• Main Author: Sakrikar, Satish Dinkar
• Published: University of Warwick 1972
• Subjects: 540; QD Chemistry
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595001

Evidence is presented in this thesis for the possible involvement of a novel olefinic π-complex of cobalt (III) in the solvolysis of β -acetoxyalkylcobaloximes. The enzymatic reactions catalysed by coenzyme B12 are described in the introduction. Evidence obtained from an extensive study of these reactions, and reported in literature, is discussed in terms of various mechanisms for coenzyme B₁₂ action. The similarity between biacetyldioxime complexes of cobalt and the B₁₂ coenzymes is described and, on the basis of studies on the former (reported in Chapters II and III), the suggested intermediary of an olefinic π-complex of cobalt(III) in some of the enzymatic reactions can be supported. The hydrolysis, ethanolysis and deuteromethanolysis of β-acetoxyalkylcobaloximes are discussed in Chapter II. The evidence obtained, and results of studies on cobaloximes reported in literature, are interpreted in terms of a scheme which requires the involvement of the intermediate mentioned above. However, two possible alternatives to this complex are also considered The similarity of these solvolyses with the acid catalysed deoxymercuration reactions and solvolyses of substituted ferrocenes is pointed out. Chapter III deals with the solvolyses of chiral and specifically labelled cobaloximes and also of cobaloximes with different trans-ligands. The results of these experiments are shown to be in favour of the πcomplex as the key intermediate in these solvolyses.