Diisopropylamine → 4-(3,3-dimethyl-3,4-dihydro-2H-benzo[b][1,4]dioxepin-7-ylethynyl)-benzoic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a mixture under Ar of 7-ethynyl-3,3-dimethyl-3,4-dihydro-2H-benzo[b][1,4]dioxepine (6) (1.0 g), ethyl-4-bromobenzoate (1.13 g), [PdCl2(PPh3)2] (174 mg) and copper(I) iodide (94 mg) is added a degassed solution of diisopropylamine (20 ml) and THF (20 ml). The reaction mixture is stirred over night at 57° C. After addition of AcOEt (100 ml) and filtration over dicalite, the solution is washed with 1 N aq. HCl sol. (3×50 ml) and H2O (3×50 ml). The organic layer is dried over MgSO4 and the solvent is evaporated. The crude product is purified by flash chromatography (silica gel, heptane/AcOEt 9:1) followed by preparative HPLC. 756 mg of 4-(3,3-dimethyl-3,4-dihydro-2H-benzo[b][1,4]dioxepin-7-ylethynyl)-benzoic acid ethyl ester are obtained as a white solid, MS (ESI) 350.2 (M•)+.

Provenance & Evidence