Ruthenium catalysed sequential and tandem reactions

Abstract

This thesis describes the chemistry developed during a study of novel transition metal catalysed reactions.

Chapter 2 describes a novel procedure for the synthesis of 2,5-disubstituted furans via the isomerisation of 1,4-alkyne diols, avoiding the pitfalls of the traditional Paal-Knorr reaction. The initial ruthenium catalysed isomerisation is followed by an in situ cyclocondensation reaction using an acid co-catalyst in a one step route to furan derivatives. In addition the synthesis of the 1,4-dicarbonyl surrogates, 1,4-alkyne diols, is detailed.

The methodology detailed in chapter 2 is then used in the synthesis of pyrrole derivatives in Chapter 3. Replacement of the acid co-catalyst with 2 equivalents of amine allow various pyrrole derivatives to be synthesised using the 1,4-alkynediols as starting materials. Various amines can also be used from anilines, benzylamines and aliphatic amines, allowing access to a wide range of products.

Chapter 4 describes the attempted isomerisation of propargylic alcohols in a route to α, β-unsaturated esters. Using the tandem oxidation (with a sacrificial hydrogen acceptor)/decarboxylative Knoevenagel condensation of alcohols various α, β unsaturated ester derivatives were synthesised. Further optimisation allowed the fully saturated, doubly homologated ester derivatives to be synthesised using the “borrowing hydrogen” methodology.

Date of Award	1 Jun 2009
Original language	English
Awarding Institution	University of Bath
Supervisor	Jonathan Williams (Supervisor)