Carbene-Catalyzed Redox Amidations

Significance

Rovis and co-worker report a carbene-catalyzed internal redox process providing a direct route from α-reducible aldehydes 1 and amines 2 to α-reduced amides 3. Carbene precursor 4 is used for the in situ carbene formation. Cocatalyst 1-hydroxy-7-azabenzotriazole 5 (HOAt) generates activated esters 6 which undergo in situ amidation, thereby regenerating carbene 7. α,α-Di­chloro aldehydes, α,β-epoxy aldehydes, α,β-aziridino aldehydes and enals as α-reducible aldehyde component lead to α-chloro amides, β-hydroxy amides, β-amino amides and alkanamides. With some of these substrates a waste-free amidation is realized.