The reactions of N-substituted 2-(dimethylallyl)aniline compounds with phenylselanyl halides

Cyclization of the carbamate of 2-(dimethylallyl)aniline with phenylselanyl chloride (benzeneselenenyl chloride) gave a 1:1 mixture of a dihydroindole and a tetrahydroquinoline. With phenylselanyl bromide only the dihydroindo le was obtained. Addition of methanol to the silica used in the procedure t rapped the reaction at the non-cyclized stage forming a 3-methoxy-3-methyl- 2-(phenylselanyl)butyl side chain. The sulfonamide of 2-(dimethylallyl)anil ine only formed the dihydroindole with phenylselanyl chloride. The correspo nding trifluoroacetamide derivative did not form any cyclized product under the same conditions. The dihydroindole could be converted into the corresp onding alkene by oxidative removal of the phenylseleno group. 4-Ethoxycarbo nyl-2-(3,3-dimethylallyl)aniline cyclized with mercuric nitrate to give, af ter a reductive workup, a 2,2-dimethyltetrahydroquinoline. The X-ray crysta l structures of ethyl N-{2-[3-methoxy-3-methyl-2-(phenylselanyl)butyl] phen yl} carbamate and 2-[1-methyl-1-(phenylselanyl)ethyl]-1-[(4-methylphenyl)su lfonyl]indoline are reported.