Rhodium-catalyzed asymmetric ring opening of oxabicyclic alkenes with sulfur nucleophiles

The synthesis of 2-sulfanyl-1,2-dihydro-naphthalen-1-ols is described. This methodology is based on rhodium catalysis and enables various thiols to undergo an asymmetric S(N)2' ring opening of oxabenzonorbornadiene. Under the reaction conditions ([Rh(COD)Cl](2) (2.5 mol %), (S)-(R)-PPF-(PBu2)-Bu-t (6 mol %) AgOTf (7 mol %), NH4I (1.7 equiv), galvinoxyl (5 mol %) THF, 85 degreesC, aryl- and alkyl-sulfide adducts are obtained in good to excellent yield and in high enantiomeric excess (> 90% ee).