Cyclization Reactions through the SRN1 Mechanism. Reactions of o-Dihaloaromatic Compounds with Dithiolate Ions

PIERINI, A. B.; BAUMGARTNER, M. T; ROSSI, R.A.

AMER CHEMICAL SOC

Lugar: Washington; Año: 1987 vol. 52 p. 1089 - 1089

n the present paper we report the reactions of o-dihaloaromatic compounds with dithiolate ions as new cyclization reactions occurring by the S R ~ l mechanism. o-Diiodo- and o-bromochlorobenzene react under photostimulation with 3,4-toluenedithiolate ion to give good yields (~60%) of the cyclic disubstituted compound 2-methylthianthrene. The reaction occurs to a lesser extent (=20%) when the substrate was 1-bromo-2-iodonaphthalene. 2,3-Dichloroquinoxaline reacts with the same nucleophile in the dark or in the presence of radical traps to give a 100% yield of the cyclic disubstituted compound. The reaction of o-diiodobenzene with 1,2-ethanedithiolate gave a low yield of the cyclic compound benzo-1,4-dithiane. This decrease was explained in terms of fragmentation reactions of the proposed radical anions intermediates.