Claisen rearrangement of allyl imidates and thioimidates derived from lactams and thiolactams

Abstract

Allyl imidates N=C(OCH₂CH=CH₂)CH₂, derived from lactams, rearrange on heating to yield the corresponding C-allyl and N-dlyl lactams,I NHCOCHCH₂CH=CH₂ and N(CH₂CH=CH₂)COCH₂ while allyl thioimidates yield only the C-allyl thiolactams. The C-allylation is postulated to occur through a ketene acetal intermediate by way of a quasi-chair transition state. The yield of 3-allylhexahydro-2H-azepin-2-one obtained in such a rearrangement is significantly increased by the presence of 2-pyridone.