Sterically Hindered Mono(phosphines) as Supporting Ligands for the Platinum-Catalyzed Hydroamination of Amino Alkenes

Abstract

In an effort to develop more active catalysts for the intramolecular hydroamination of amino alkenes, we have investigated the application of sterically hindered mono(phosphines) as supporting ligands for platinum-catalyzed hydroamination. Here we demonstrate that mixtures of PtCl2 and di(tert-butyl)o-biphenyl phosphines such as P(t-Bu)2[2-(2-NMe2C6H4)C6H4] catalyze the hydroamination of 4-pentenyl and 5-hexenyl amines at 60–80 °C. This catalyst system tolerates a number of functional groups and catalyzes the cyclization of unsubstituted amino alkenes.