Platinum-catalyzed michael addition and cyclization of tertiary amines with nitroolefins by dehydrogenation of α,β-sp~3 C-H bonds

摘要

A mild platinum-catalyzed oxidative dehydrogenation of α,β- C(sp~3)-H bonds of tertiary amines in the presence of ambient oxygen is revealed, and the in situ formed enamines subsequently reacting with various nitroolefins resulted in the development of two one-pot synthetic protocols involving Michael addition-elimination and Michael addition-cyclization. By using different functionalized nitroolefins compatible with the current oxidative conditions, two types of structurally divergent products, trisubstituted enamines and chromano[2,3-b]piperidines, could be expediently accessed, respectively.