Student

Chapter 1: The application of organic chemistry to the

synthesis of phosphines

1.1: Introduction

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Organophosphorus compounds are widely used in the chemical, agricultural

and pharmaceutical industries. Phosphines have been utilised as ligands and

reagents in the synthesis of bulk chemicals and numerous fine and speciality

chemical intermediates. 1

The synthesis of phosphine ligands for transition-metal catalysed reactions

with the intention of determining the features in a given ligand that affect the

reactions required, for the purpose of the present project, the synthesis of

often complex phosphorus ligands. This synthesis involved the application of

the directed ortho-metallation (DoM) to incorporate the functionality into the

ligand for effective determination of these features.

This literature chapter is therefore divided into four sections, with the view to

introducing the reader to the pertinent literature and also to the concepts

required to place the present work into context, namely:

1. General routes to the synthesis of phosphines

2. Current methods used to synthesise asymmetric phosphines

3. Current phosphine ligands and their application to palladium catalysis

4. The DoM reaction and some of its applications

1.2: The synthesis of phosphines

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The use of an electron-rich trivalent phosphorus centre for addition to or

substitution at an electrophilic site is a long-established approach to the

formation of carbon-phosphorus bonds. 2 Phosphines can be synthesised via

a variety of methods

1

1.2.1: Substitution reactions using neutral trivalent phosphorus

reagents

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The well-known Michaelis-Abruzov reaction is historically the fundamental

approach to generating C-P bonds. It involves the use of a neutral trivalent

phosphorus reagent undergoing a reaction with a carbon centre containing a

leaving group. 3

CH 3O

(CH 3O)3P

+

Cl

CH 3O

OCH 3

P...