SULFUR-BRIDGED CARBOCYCLES .2. EXTRUSION OF SULFUR BRIDGE

The extrusion of the sulfur bridge from 7-thiabicyclo[2.2.1]heptane (1a) and 9-thiabicyclo[3.3.1]nonane (1b) and their derivatives, a synthetically useful procedure for the controlled formation of transannular single and double bonds, is described. A novel synthesis of ∆1.5-bicyclo[3.3.0]octene (8) has been achieved through the Ramberg-Backlund rearrangement of l-bromo-9-thiabicyclo[3.3.1]nonane 9,9-dioxide (7). Thermal extrusion of sulfur dioxide from 7-thiabicyclo[2.2.1]heptane 7,7-dioxide (4) and 9-thiabicyclo[3.3.1]nonane 9,9-dioxide (5) affords 1,5-hexadiene and bicyclo[3.3.0]octane (14), respectively, as major products. Photochemical extrusion of sulfur from la and lb in trivalent organophosphorus solvents affords, as the major products, cyclohexene and an equimolar mixture of 14 and cyclooctene, respectively. Related studies on the photochemical extrusion of sulfur from bivalent sulfur compounds in organophosphorus solvents are also described. © 1969, American Chemical Society. All rights reserved.