4,5-Diphenyloxazole → (R)-2-(4,5-diphenyloxazol-2-yl)-1-trimethylsilyloxy-1-[3-(tertbutyldiphenylsiloxy)benzyl]-2-cyclohexene

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Reaction Steps

To a solution of (4,5-diphenyl)oxazole (17 g) in THF (100 ml) was added n-BuLi (57 ml, 1.6N-solution in hexane) at −78° C. After stirring for 30 minutes, a solution of (R)-1-[3-(tertbutyldiphenyl-silyloxy)benzyl]-1-trimethylsilyoxy-2-cyclohexanone (27 g) in THF (50 ml) was added to the above mixture at the same temperature. After stirring for 1 hour, the reaction mixture was partitioned between EtOAc and water. The organic layer was washed with 1N-HCl solution and brine. The organic solvent was evaporated in vacuo to give a residue. The residue was dissolved in toluene (100 ml) and then added with (methoxycarbonylsulfamoyl)triethyl-ammonium hydroxide, inner salt(20.4 g) at room temperature. After refluxing under stirring for 5 hours, the reaction mixture was evaporated in vacuo. The residue was purified by chromatography on silica gel to give (R)-2-(4,5-diphenyloxazol-2-yl)-1-trimethylsilyloxy-1-[3-(tertbutyldiphenylsiloxy)benzyl]-2-cyclohexene (36 g).

Provenance & Evidence