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 SN2‘ ring opening of oxabenzonorbornadiene. Under the reaction conditions ([Rh(COD)Cl]2 (2.5 mol %), (S)-(R)-PPF-PtBu2 (6 mol %), AgOTf (7 mol %), NH4I (1.7 equiv), galvinoxyl (5 mol %), THF, 85 °C), aryl- and alkyl-sulfide adducts are obtained in good to excellent yield and in high enantiomeric excess (>90% ee).