5-fluoro-3H-2-benzofuran-1-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: According to a similar procedure to that described in Example 4-(5), 5-fluoro-1(3H)-isobenzofuranone (described in Tetrahedron, 44, 4591 (1988); 1.52 g, 10 mmol) was reacted with an aqueous solution of sodium hydroxide (1.008N; 10 ml, 10 mmol), 4-methoxybenzyl chloride (1.57 g, 10 mmol), tetrazole (1.40 g, 20 mmol), bis(allyloxy)(diisopropylamino)phosphine (described in Tetrahedron Lett., 30, 4219 (1989); 3.05 g, 12.4 mmol), and tert-butyl hydroperoxide (80% di-tert-butyl peroxide solution; Merck; 2.7 g, 24 mmol), and the reaction mixture was worked up to afford, after extraction, an oily residue. The residue was subjected to chromatography on a silica gel (75 g) column (eluent; ethyl acetate:hexane=2:1˜3:1) to afford an oily mixture. The mixture was further subjected to chromatography on a silica gel (50 g) column (eluent; ethyl acetate:hexane=1:4˜1:2) to afford the title compound (2.07 g, 46% yield) as a colorless oil. to afford after extraction to afford an oily mixture