Transition-Metal-Catalyzed Functionalization of Propargylic Alcohols and Their Derivatives

Abstract

Propargylic alcohols are valuable starting materials in organic synthesis; they are easily accessible and can be functionalized further, either through the triple bond or the alcohol functionality. Certain transition metals such as ruthenium or gold have an affinity for propargylic alcohols or alkyne units, which allows for catalytic activation of these substance classes. This review article provides a survey of various transition-metal-catalyzed functionalizations of propargylic alcohols with an emphasis on the latest literature. Examples of nucleophilic propargylic substitution reactions, allene formation, addition and coupling reactions, cyclization reactions, Meyer–Schuster, Rupe and redox–isomerization reactions are given in the article, along with the scope and limitations of the corresponding transformations and mechanistic considerations. 1 Introduction 2 Nucleophilic Propargylic Substitution Reactions 2.1 Nucleophilic Propargylic Substitution Reactions with Propargylic Alcohols 2.2 Nucleophilic Substitution Reactions Employing Propargylic Esters 2.3 Propargylic Amination Reactions 2.4 Mechanisms 3 Allene Formation 4 Addition and Coupling Reactions Involving the Alkyne Unit 5 Cyclization Reactions 5.1 Intramolecular Cycloisomerization or Substitution Reactions 5.2 Intramolecular Cyclization Reactions Preceded by a Propargylic Substitution or Addition Reaction 6 Isomerization Reactions 6.1 Meyer–Schuster Rearrangements 6.2 The Rupe Rearrangement 6.3 Redox Isomerizations 7 Conclusion and Outlook