Oxone-Promoted Synthesis of 4-(Chalcogenyl)isoquinoline-N-oxides from Alkynylbenzaldoximes and Diorganyl Dichalcogenides.

We report a protocol for the synthesis of 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides via electrophilic cyclization between alkynylbenzaldoximes and diorganyl dichalcogenides promoted by Oxone. A total of 21 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides were selectively obtained in yields of up 93% under an ultrasound irradiation condition in short reaction times (10-70 min). Additionally, the synthetic usefulness of the 3-phenyl-4-(phenylselanyl)isoquinoline-2-oxide was demonstrated in the annulation reaction with 1-(2-bromophenyl)-3-phenylprop-2-yn-1-one and in the deoxygenation reaction with phenylboronic acid.