The reaction of enamides with CAN in methanol affords variously functionalized β-lactams through a 4-exo-trig cyclization of α-carbamoylalkyl radicals; in most cases products with trans stereochemistry can be obtained.
Reaction of variously substituted enamides with Mn(OAc)(3) . 2H(2)O afforded beta-lactamic products in modest to good yields, depending mostly on the solvent and reaction conditions. The substitution pattern of the enamidic double bond was found of primary importance for the outcome of the reaction. (C) 1997 Published by Elsevier Science Ltd.
Mn(III) — promoted cyclization of enamides: An oxidative radical approach to β-lactams
α-Caibomethoxy-N-vinylamides were reacted with Mn(OAc)3 in glacial acetic acid at 70 °C to afford variously substituted β-lactams in good yields and short reaction times.