Triethylsilane → (R)-2-[2-amino-2-(3-methyl-1,2,4-oxadiazol-5-yl)-ethylsulfanyl-methyl]-3-[dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-5-methoxy-6-methylbenzoic acid allyl ester

Participants

Reaction Steps

To a solution of 13.8 g of 2-formyl-5-methoxy-6-methyl-3-[dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-benzoic acid allyl ester in 38 ml of trifluoroacetic acid, cooled to 0° C., were added within 15 min a solution of 13.7 g of (R)-2-mercapto-1-(3-methyl-1,2,4-oxadiazol-5-yl)ethylcarbamic acid tert-butyl ester and 6.2 g of triethylsilane in 38 ml of dichloromethane. The solution was kept at 0° C. for 18 h and then evaporated in vacuo. The residue was taken up in ethyl acetate and the solution was successively washed with water; saturated sodium carbonate solution and brine, and dried over sodium sulfate. The solvent was evaporated in vacuo and the residue Was chromatographed on silica gel using ethyl acetate/hexane (1:3, v/v) as eluent to yield 14.1 g of (R)-2-[2-amino-2-(3-methyl-1,2,4-oxadiazol-5-yl)-ethylsulfanyl-methyl]-3-[dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-5-methoxy-6-methylbenzoic acid allyl ester as a pale yellow oil.

Provenance & Evidence