The chemoselectivity in the palladium-catalyzed intramolecular cyclization
of 2-(o-bromoaryl)alkenenitriles depends on the nature of alpha-substituten
ts. 2-(o-Bromoanilino)alkenenitriles attacked the cyano group, followed by
the cyano group transposition and hydrolysis, to give o-(methylamino)benzon
itrile. 2-(o-Bromobenzyl)alkenenitriles, 2-(o-bromophenylthio)alkenenitrile
s and 2-(o-bromophenoxy)-alkenenitriles attacked the olefinic double bonds
and led to 1-vinyl-2-indancecarbonitrile, 1,2,3,4-tetrahydronaphthalene-2-c
arbonitriles, 3,4-dihydro-2H-benzo[b]oxine-2-carbonitriles, and 3,4-dihydro
-2H-benzo[b]oxine-2-carbonitriles. A general mechanism for the palladium-ca
talyzed arylations is proposed.