Dramatically different photochemical behaviour of 1-aroyl-2-methylene piperidine and pyrrolidine derivatives. An expeditious synthesis of ruspolinone

Article abstract of DOI:10.1016/0040-4039(96)01765-0

Upon irradiation in neutral solvent, the diversely substituted 1-aroyl-2-methylenepiperidines 6a-f give rise to photocyclized products 4a-f while their pyrrolidine congeners 7a,c,d afford enaminoketones 18a,c,d products of photo-Fries rearrangement.