Amidomercuration-Cyclization of N-tert-Butoxycarbonyl-2-allylaniline Derivatives

Article abstract of DOI:10.3987/COM-93-6409

Dilithiation of N-tert-butoxycarbonylanilines with tert-butyllithium followed by addition of 4-bromo-2-methyl-2-butene affords N-tert-butoxycarbonyl-2-(3,3-dimethylallyl)anilines (3a-e).The mercuric ion-initiated cyclization of compounds (3a-e) was investigated.N-tert-Butoxycarbonyl-4-chloro-2-(3-methyl-2-buten-1-yl)aniline (3b) and the 6-fluoro analogue (3c) readily undergo amidomercuration-cyclization to give N-tert-butoxycarbonyl-5-chloro-2,2-dimethyl-1,2,3,4-tetrahydroquinoline (4b) and N-tert-butoxycarbonyl-8-fluoro-2,2-dimethyl-1,2,3,4-tetrahydroquinoline (4c).Anilides (3a, 3d-e) gave a mixture of tetrahydroquinolines (4a, 4d-e) and the dihydroindoles (5a, 5d-e).N-Ethoxycarbonyl-2-(3-methyl-2-buten-1-yl)aniline (3f) gave mainly the N-ethoxycarbonyl-2,2-dimethyl-1,2,3,4-tetrahydroquinoline (4f).