π-Acid Mediated Insertion of Alkynes into Carbon–Heteroatom σ-Bonds

Abstract

The rapidly expanding field of gold and platinum π-acid catalysis has led to the discovery of diverse transformations that are initiated with nucleophilic attack onto a metal-activated alkyne. This review brings together those reactions which employ a heteroatom nucleophile bearing a functional group that can subsequently migrate to effect a formal insertion of the alkyne into a carbon–heteroatom­ σ-bond. This reactivity profile is encountered in a range of efficient and powerful cycloisomerisations for the preparation of carbo- and heterocycles. 1 Introduction 2 1,2-Addition of Carbon–Heteroatom Bonds across Alkynes 2.1 Heteroatom-to-Carbon Allyl Migrations 2.2 Accessing Sigmatropic Rearrangements 2.3 Related Palladium-Catalysed 1,2-Carboalkoxylations and Carboaminations 2.4 Beyond Allyl Migration in the 1,2-Carbofunctionalisation of Alkynes 2.5 Oxonium Ion Migration 2.6 Migrating Centres at Higher Oxidation Levels 2.7 Migration of Heteroatoms 3 1,5 Heteroatom-to-Carbon Migrations 3.1 Alkynyl Benzoates as Alkylating Agents 4 Internal versus External Migrations 4.1 Internal Migrations of Oxonium Species 5 1,1-Carbofunctionalisations 6 Application in Natural Products 7 Summary and Conclusions