Catalytic enantioselective synthesis of the phosphodiesterase type IV inhibitor (R)-(-)-rolipram via intramolecular C-H insertion process
A new route to the phosphodiesterase type IV inhibitor (R)-(-)-rolipram (1) has been developed, wherein the key step relies on enantioselective intramolecular C-H insertion of N-alkyl-N-4-nitrophenyl-α-methoxycarbonyl- α-diazoacetamide 7 catalyzed by chir