Iodosodilactone

Typical procedure for preparation of esters and regeneration of iodosodilactone : A mixture of iodosodilactone (1.74 g, 6 mmol) and DMAP (733 mg, 6 mmol) in CHCl₃ (50 mL) is stirred under refluxing in air for 1 h. Then, carboxylic acid (7 mmol), alcohol (611 mg, 5 mmol) and PPh₃ (1.3 g, 5 mmol) are added in sequence. The mixture is refluxed for 4 h. The reaction is quenched with saturated sodium bicarbonate solution (30 mL). The aqueous layer is extracted with CH₂Cl₂ (50 mL×3). The combined organic layer is dried with Na₂SO₄, and concentrated to afford the crude product, which is purified by silica gel flash chromatography to give the corresponding ester.
The aqueous layer is acidified with 5 N HCl (pH < 7), and most of water is removed in vacuo to give the crude material. Conc. HCl (15 mL) is poured into the residue, and aq. 5.8% NaOCl soln. (35 mL) is added dropwise to the vigorously stirred mixture at room temperature. After the addition of NaOCl is complete, stirring is continued for a further 4 h. The precipitated white solid is collected by filtration, washed with H₂O, diethyl ether, and acetone, and dried at room temperature to give 1.63 g of iodosodilactone in 94% recovery yield.