Organocatalytic Group Transfer Reactions with Hypervalent Iodine­ Reagents

In recent years, a plethora of synthetic methods that employ hypervalent iodine compounds donating an atom or a group of atoms to an acceptor molecule have been developed. Several of these transformations utilize organocatalysis, which complements well the economic and environmental advantages offered by iodine reagents. This short review provides a systematic survey of the organocatalytic approaches that have been used to promote group transfer from hypervalent iodine species. It covers both the reactions in which an organocatalyst is applied to activate the acceptor, as well as those that exploit the organocatalytic activation of the hypervalent iodine reagent itself. 1 Introduction 2 Organocatalytic Activation of Acceptor 2.1 Amine Catalysis via Enamine and Unsaturated Iminium Formation 2.2 NHC Catalysis via Acyl Anion Equivalent and Enolate Formation 2.3 Chiral Cation Directed Catalysis and Brønsted Base Catalysis via Pairing with Stabilized Enolates 3 Organocatalytic Activation of Hypervalent Iodine Reagent 3.1 Brønsted and Lewis Acid Catalysis 3.2 Lewis Base Catalysis 3.3 Radical Reactions with Organic Promoters and Catalysts 4 Summary and Outlook