SYNTHESIS OF THIENOTHIEPINOFURANS AND THIEPINODIFURANS NOVEL SYNTHESIS OF HETEROCYCLIC THIOLACTONES AND 3-FURYL KETONES

The synthesis of thienothiepinofurans and thiepinodifurans is describe d. The displacement reaction between lithium furan-2-thiolate and 2-br omomethyl-substituted thiophenes and furans gave the expected thioethe r. The cyclization of thioether with polyphosphoric acid (PPA) in xyle ne gave thiepinone derivatives and heterocyclic thiolactones. The form ation of the latter compounds can be explained in terms of a cyclizati on via the sulfur atom. The desulfuration with Raney nickel gave 3-fur yl ketones in good yields.