Development of the Ti-catalyzed intermolecular hydroamination of alkynes

This account describes the development of Ti-catalyzed intermolecular hydroamination reactions of alkynes, achieved in the author's laboratories during the last five years. Starting from initial ideas and early results with Cp2TiMe2 as a catalyst precursor, mechanistic studies and applications of Cp2TiMe2-catalyzed hydroaminations of alkynes for the synthesis of biologically interesting classes of compounds are presented. Particular attention is paid to the identification of improved second generation catalysts such as Cp*2TiMe2 and Ind(2)TiMe(2). 1 Introduction 2 Initial Ideas 3 CP2TiMe2: The First Generation Catalyst 4 CP*2TiMe2: The Improved Catalyst 5 Other Titanium Catalysts 6 Ind2TiMe2: The General Catalyst 7 Hydroamination Reactions Employing Enantiomerically Pure Amines 8 Applications for the Synthesis of Biologically Interesting Compounds 9 Summary and Outlook