Borrowing Hydrogen in the Synthesis of Alcohols and Amines

Abstract

This thesis is concerned with the transformation of carbonyl compounds and allylic alcohols (and some amines) into alcohols via the process of transfer hydrogenation. The main work develops the idea of a new hydrogen donor for transfer hydrogenation and then applies it to an impressive one pot reaction. The transformation of amines shows an unexpected reaction and investigation into this reveals a possible mechanism for the reaction. Chapter 2: 1,4-Butanediol is introduced as a new hydrogen donor. It is used to convert a wide range of carbonyl substrates successfully into their alcohol counterparts after optimisation of conditions. A comparison with other straight chain alkanediols proves that 1,4-butanediol is the most suitable diol to use. The asymmetric aspect of the chemistry is investigated, but the results obtained do not compare to those already published in the literature. Chapter 3: A one pot reaction of isomerisation and reduction of allylic alcohols is proposed and proven. This is achieved by using 1,4-butanediol as the solvent and hydrogen donor. A wide range of allylic alcohols are converted to their corresponding saturated alcohols. The conditions were not applicable to asymmetric results. Chapter 4: The reaction of straight chain alkanediols with themselves is discovered and investigated to find they produce cyclic acetals. Results vary depending on the length of the alkyl chain. A series of experiments improved initial results to complete conversion. However isolation of these compounds remains a problem and requires more work. Chapter 5: During the synthesis of Diphenhydramine, an unexpected rearrangement reaction was discovered. This reaction was found to be specific to a certain structural arrangement on the compound. Investigations using 13C labelling found a plausible mechanism to explain the reaction.

Date of Award	1 Mar 2010
Original language	English
Awarding Institution	University of Bath
Supervisor	Jonathan Williams (Supervisor)