Alkoxycarbonylcarbene Transfer to Acyclic Tertiary Enaminones

Article abstract of DOI:10.1002/prac.19983400405

Copper-catalyzed alkoxycarbonylcarbene transfer from methyl or tert-butyl diazoacetate to acyclic enaminoesters 6a,b and enaminocarboxanilide 13 yields vicinal push-pull-substituted cyclopropanes 7a,b, 8, and 14. In contact with dry silica gel, the latter compounds undergo facile ring-opening leading to enaminoesters 9,10, and 15. Treatment with aqueous acid transforms 9 and 10 into 2-acylsuccinates 11 and 12, and 15 into pyrrolinone 16. Methoxycarbonylcarbene transfer to enaminoketones 1a-c does not yield isolable cyclopropanes, but after hydrolytic work-up α-acyl-γ-ketoesters 2a-c are obtained.