Concerning the synthesis and enantioselective rearrangements of episulfoxides

A novel synthesis of episulfoxides having the norbornane skeleton is possible by use of a rhodium catalyst to effect SO transfer from trans-stilbene episulfoxide to norbornene or norbornadiene. Analogous Rh-2(OAc)(4) catalysed sulfur transfer to these alkenes is also possible using propylene sulfide as the sulfur source. These methods did not give useful yields of products with alternative types of alkene substrate. A novel type of chiral lithium amide base reaction, involving the rearrangement of certain types of symmetrical ring-fused episulfoxides, gives alkenyl sulfoxide products in up to 88% ee. The structures of the products, including absolute stereochemistry, were assigned based on X-ray crystal structure determinations.