A facile synthesis of (±)-sesbanine via γ-addition of ketene silyl acetal with quaternized methyl nicotinate

Total synthesis of (±)-sesbanine ( 1 ) was carried out using γ-addition of ketene silyl acetal of methyl 3-cyclopentenecarboxylate to quaternized methyl nicotinate. The resulting 1,4-dihydropyridine ( 7 ) was oxidized with DDQ to give 4-substituted nicotinate ( 2 ) and 2 was converted to alcohol ( 8 ) by stereoselective oxymercuration followed by treatment with ammonia to give 1 .