γ-Lactam synthesis via C-H insertion: Elaboration of N-benzyl protecting groups for high regioselectivity toward the total synthesis of rolipram
(Matrix presented) By intramolecular C-H insertion of α-diazo-α -(phenylsulfonyl)acetamides, γ-lactams such as the antidepressant agent rolipram were efficiently synthesized in a highly regioselective manner. N-Benzyl moieties were elaborated as amide protecting groups to enhance regioselectivity in C-H activation as well as chemoselectivity over addition reactions.