Catalytic tandem markovnikov hydroamination-alkynylation and markovnikov hydroamination-hydrovinylation

Abstract

A tandem hydroamination-alkynylation was developed as a unique mode of accessing tetrasubstituted propargylic amines. The first equivalent of an alkyne acts as the electrophile in a Markovnikov hydroamination. The resultant ketimine intermediate is attacked by the second equivalent of alkyne in its nucleophilic copper acetylide form. Studies on the role of each component indicate that the overall reaction is first-order in copper, amine, and alkyne. In addition, a tandem hydroamination-hydrovinylation provides for an unprecedented onestep synthesis of a 1-amino-1,3-butadiene from phenylacetylene and morpholine.