DIRECT SYNTHESIS OF 2-NORBORNANONE DITHIOACETALS FROM 2-CYCLOPENTENONE DITHIOACETALS AND DIENOPHILES - SYNTHETIC APPLICATION OF THERMAL INTERCONVERSION BETWEEN CYCLIC DITHIOACETALS AND THE RING-OPENED VINYL SULFIDE FORMS

Readily accessible 1,3-dithiane and 1,3-dithiolane derivatives of 3-su bstituted 2-cyclopentenones react with a variety of dienophiles via th e in situ generated 1,3-cyclopentadien-2-yl sulfide tautomers, in acet onitrile at 120 degrees C to give 2-norbornanone dithioacetals in 79-9 3% yields. This transformation represents, to our knowledge, the first synthetic application of thermal interconversion between cyclic dithi oacetals and the ring-opened vinyl sulfide forms. Copyright (C) 1996 E lsevier Science Ltd