反应详情

Following the general procedure for the preparation of acyloxyalkyl/alkoxycarbonyloxyalkyl carboxylic esters from carboxylic acids of Description 22, (2R)-4-[(3-chloropropyl)sulfonyloxy]-3,3-dimethyl-2-(phenylmethoxy)butanoic acid (11) (0.5 g, 1.3 mmol) dissolved in 10 mL of anhydrous toluene was reacted with 1.1 g (4.0 mmol) of chloromethyl 2-phenylacetate in the presence of 0.44 g (1.6 mmol) of silver carbonate (Ag2CO3). After work-up, the crude material was purified by silica gel column chromatography using a mixture of ethyl acetate (EtOAc) and hexane (Hxn) (EtOAc/Hxn=1:2) as eluent to provide 0.44 g (64% yield) of the title compound (28a) as a colorless oil. Rf=0.47 (EtOAc/Hxn=1:2). 1H NMR (400 MHz, CDCl3): δ=0.97 (s, 3H), 0.99 (s, 3H), 2.24-2.30 (m, 2H), 3.20-3.24 (m, 2H), 3.62-3.65 (m, 2H), 3.68 (s, 2H), 3.84 (s, 1H), 3.91 (d, J=9.2 Hz, 1H), 4.15 (d, J=9.6 Hz, 1H), 4.28 (d, J=10.8 Hz, 1H), 4.53 (d, J=11.2 Hz, 1H), 5.78 (d, J=5.6 Hz, 1H), 5.87 (d, J=5.6 Hz, 1H), 7.25-7.38 (m, 10H) ppm. MS (ESI) m/z 548.99 (M+Na)+. The analytical data was consistent with the proposed structure.

1. customAfter work-up, the crude material was purified by silica gel column chromatography
2. additiona mixture of ethyl acetate (EtOAc) and hexane (Hxn) (EtOAc/Hxn=1:2) as eluent