Synthesis of New γ-Lactams with gem-Difluorinated Side Chains

Abstract

A short and efficient approach has been designed for the synthesis of new γ-lactams that feature gem-difluorinated side-chains in position 4. The key steps involve 1,4-addition of nitroalkane anions on electrophilic gem-difluoroalkenes, followed by a cascade nitro reduction–heterocyclization. This flexible strategy also allows easy introduction of substituents in positions 3 or 5.

Origin of High Diastereoselectivity in Reactions of Seven‐Membered‐Ring Enolates

“…(3)]. The observed preference for anti‐alkylation is consistent with what has been observed with other endocyclic enolates that bear β‐alkyl substituents, regardless of ring size [2a, 3c,d, 8b, 13] . The favored conformer of the enolate 9 would position the substituent pseudoequatorially, leaving the peripheral face exposed [Eq.…”