(R)-3,3'-Bis[[[(1R,2R)-2-(isoindolin-2-yl)-1,2-diphenylethyl]imino]methyl]-1,1'-bi-2-naphthol

General procedure of the enantioselective iodolactonization: A mixture of 1 (0.001 mmol) and Zn(OAc)₂ (0.003 mmol) is stirred for 0.5 hour in anhydrous dichloromethane (1.0 mL) at rt. After cooling the mixture to -78 °C, carboxylic acid (0.1 mmol) in toluene (3.0 mL) is slowly added to the resulting yellow solution and stirred for 0.5 hour at the same temperature. Then, N-iodosuccinimide (NIS) (24.6 mg, 0.11 mmol) and I₂ (5.0 mg, 0.02 mmol) are added to the reaction mixture. After being stirred for appropriate time, the reaction mixture is quenched with saturated Na₂SO₃ aq. and 1N NaOH aq., and then the products are extracted with dichloromethane 3 times. The collected organic layer is dried over Na₂SO₄. After removal of the solvent under reduced pressure, the residue is purified by silica-gel column chromatography (hexane/acetone=8/1) to afford the iodolactone.