The first reaction of Dimethoxycarbene with an imine moiety

Abstract

The nucleophilic dimethoxycarbene (DMC; 2) generated by thermal decomposition of 2,5-dihydro-1,3,4-oxadiazole derivative 1 in boiling toluene reacts smoothly with N-(9H-fluoren-9-ylidene)-4-methylbenzenesulfonamide (7b) to yield carbonimidoate derivative 10. A multi-step reaction pathway, initiated by the attack of DMC onto the C=N bond and followed by the migration of the sulfonyl group (or via a sulfinate anion) is proposed to explain the formation of the final product. In contrast to the formal ketimine 7b, N-benzylidene-4-methylbenzenesulfonamide (7a), a formal aldimine, does not react with DMC under comparable conditions.