Fig. 5: Series of mechanistic studies and proposed catalytic cycle.
From: Catalytic diazene synthesis from sterically hindered amines for deaminative functionalization
a Intermediate formations of 17 and 18 with DBDMH. b Control experiments without copper suggested that a copper catalyst significantly facilitated the formation of 2a. c Control experiments without DBU indicated that DBU was crucial for efficient reaction progress. d EPR analysis of DMPO adduct 24. e Proposed catalytic cycle. The halogen atom abstraction would first proceed with intermediate A to generate copper (II) species and aminyl radical species C. Copper(III) species B formation would be feasible, but aminyl radical generation would be unfavorable. The N–N bond formation proceeds through aminyl radical species C with D to afford intermediate E.
