Preparation of a New Chiral Non-Racemic Sulfur-Containing Diselenide and Applications in Asymmetric Synthesis

The synthesis of the new chiral non‐racemic sulfur‐containing diselenide, di‐2‐methoxy‐6‐[(1 S)‐1‐(methylthio)ethyl]phenyl diselenide, is described. When treated with ammonium persulfate this diselenide is transformed into the corresponding selenenyl sulfate, which acts as a strong electrophilic reagent and adds to alkenes, in the presence of methanol or water, to afford the products of selenomethoxylation or selenohydroxylation, respectively, with excellent diastereoselectivities. Starting from alkenes containing internal nucleophiles, asymmetric cyclofunctionalization reactions also resulted in good chemical yields, complete regioselectivities, and high diastereoselectivities. This sulfur‐containing diselenide can also be used in catalytic amounts to promote one‐pot selenenylation–deselenenylation processes, from which several types of products can be obtained in high yield and with good enantiomeric excess. Excellent diastereoselectivities have been achieved with the new sulfur‐containing optically active diselenide 1 in both enantioselective addition reactions to alkenes (see scheme) and ring‐closure reactions. The efficient transfer of chirality is attributed to a strong interaction between the selenium and sulfur atoms. The diselenide 1 can also be used in catalytic amounts to promote one‐pot selenenylation–deselenenylation processes, from which several types of products can be obtained in high yield and with good enantioselectivity.