CSC.B.[Si]([O:12][CH2:13][CH2:14][S:15][C:16]1[CH:17]=[C:18]([CH:22]=[CH:23][CH:24]=1)[C:19](O)=[O:20])(C(C)(C)C)(C)C.Cl>C1COCC1>[OH:20][CH2:19][C:18]1[CH:17]=[C:16]([S:15][CH2:14][CH2:13][OH:12])[CH:24]=[CH:23][CH:22]=1Borane dimethyl sulfide complex (2M in THF, 17.3 mL) was added dropwise to an ice cold solution of 3-(2-(tert-butyldimethylsilyloxy)ethylthio)benzoic acid [Aromatic Intermediate 16, step a] (2.16 g) in THF (50 mL). The reaction was allowed to warm to RT, then heated at reflux for 2 h. The reaction was cooled in an ice bath and aqueous HCl solution (2M, 50 mL) was added dropwise. The resulting mixture was stirred overnight. The reaction was concentrated to half its original volume and the resulting aqueous extracted with DCM (3×100 mL). The combined organics were washed with brine (100 mL), dried over sodium sulphate, filtered and evaporated. The residue was purified by silica gel chromatography eluting with 4:1 isohexane:ethyl acetate to 100% ethyl acetate gradient. The fractions containing product were combined and evaporated to give the subtitled compound as a clear oil. Yield 0.77 g.
Wird geladen…
