Highly Selective Construction of Medium-Sized Lactams by Palladium-Catalyzed Intramolecular Hydroaminocarbonylation of Aminoalkynes

A novel palladium-catalyzed intramolecular
hydroaminocarbonylation
of aminoalkynes has been developed. This direct and operationally
simple protocol provides a rapid and reliable approach to a diverse
array of valuable seven- and eight-membered lactams with high chemoselectivity
and regioselectivity. The high selectivity might be attributed to
rational tuning the electronic nature of the amine moiety and the
palladium catalyst, which enabled this transformation to proceed in
the absence of acidic or any other additives under fairly mild reaction
conditions. This method paves the way for the synthesis of medium-sized
lactams.