Difunctionalization of the C-N Bond through tert-Butylnitrite-Initiated C-N Cleavage of 1,2,3,4-Tetrahydroisoquinolines and N,N'-Diarylimidazolidines under Transition-Metal-Free Conditions.

Difunctionalization of the saturated C-N bond of 1,2,3,4-tetrahydroisoquinolines and N,N'-diarylimidazolidines was achieved using TBN as the metal-free initiator, providing a series N-nitrosoaminoaldehydes in high yields. Mechanistic study shows that the TBN-derived tBuO radical initiated the sp3 C-H bond activation, and the C-N bond cleavage was mediated by an iminium intermediate. This reaction provided a new way to cleave an inert C-N bond under mild and metal-free conditions, realizing the construction of molecular complexity through difunctionalization of the C-N bond.