STEREOCHEMISTRY AND MECHANISM OF THE BASE-INDUCED LOSS OF THIOPHENOL FROM 1,1,3-TRIS(PHENYLTHIO)ALKANES TO FORM CYCLOPROPANONE DITHIOKETALS

The indicated aspects of the title reaction were investigated by subjecting frans-2-(bis(phenylthio)-me thyl)-1 - (phenylthio)cyclohexane (9) and the corresponding cis isomer (5) to the action of methyllithium for 50 h and quenching the mixtures with deuterium oxide. The trans isomer gave the ring-closed product (10) in 51%) yield, and 29% of the undeuterated starting material was recovered. The cis isomer gave a variety of decomposition products, 13% of starting material which was completely deuterated at the thioacetal carbon atom, and no ring-closed product (10). It is concluded that the ring closure is an intramolecular nucleophilic displacement of phenylthiolate ion by the thioacetal anion. © 1979, American Chemical Society. All rights reserved.