反应详情

To a solution of 4-methylbenzyl-O-benzylphosphinic acid (2, R=4-methylbenzyl)(2.16 g, 8.3 mmol) in THF (15 mL) was added sodium hydride (0.10 g, 60 % dispersion in oil) followed by dibenzyl 2-methylenepentanedioate at 0 C., and the mixture was stirred at rt for 4 h. The reaction mixture was then diluted with EtOAc (50 mL) and poured into 1N HCl (50 mL). The organic layer was separated, dired over Na2SO4, and concentrated. This material was purified by silica gel chromatography (hexanes: EtOAc, 4:1 to 1:1) to give 3.41 g of 2,4-di(benzyloxycarbonyl)butyl(4-methylbenzyl)-o-benzylphosphinic acid (4, R=4-methylbenzyl)as colorless oil (70% yield): Rf 0.61 (EtOAc) ; 1H NMR (CDCl3) delta 1.6-1.8 (m, 1 H), 1.9-2.0 (m, 2 H), 2.1-2.4 (m, 6 H), 2.7-2.9 (m, 1 H), 3.05 (dd, J=9.0, 16.8 Hz, 2 H), 4.8-5.1 (m, 6 H), 7.0-7.1 (m, 4 H), 7.2-7.4 (m, 15 H).

1. customThe organic layer was separated
2. concentrationconcentrated
3. customThis material was purified by silica gel chromatography (hexanes: EtOAc, 4:1 to 1:1)