反应详情

To a solution of 1,3-dichloro-4-triisopropylsilyloxybenzene (6.00 g) in tetrahydrofuran (50 ml) at -60° C. was added dropwise n-butyllithium, 1.6M solution of hexane (12.9 ml) over 30 minutes under nitrogen and the mixture was stirred for 1 hour at the same temperature. A solution of ethyl chloroformate in tetrahydrofuran (20 ml) was added dropwise to the mixture over 20 minutes at -60° C. The resulting mixture is stirred for 1 hour at -60° C., the cooling bath was removed, and temperature was allowed to rise to 20° C. A solution of ammonium chloride (2 g) in water (37 ml) was then added over 5 minutes followed by ethyl acetate (40 ml) and brine (40 ml). The organic layer was separated, washed with water and brine, dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel eluting with a mixture of ethyl acetate and hexane (1:10 to 1:6) to give ethyl 2,6-dichloro-3-triisopropylsilyloxybenzoate (1.59 g) as an oil.

1. stirringThe resulting mixture is stirred for 1 hour at -60° C.
2. customthe cooling bath was removed
3. customto rise to 20° C
4. additionA solution of ammonium chloride (2 g) in water (37 ml) was then added over 5 minutes
5. customThe organic layer was separated
6. washwashed with water and brine
7. dry with materialdried over magnesium sulfate
8. customevaporated in vacuo
9. customThe residue was chromatographed on silica gel eluting with a mixture of ethyl acetate and hexane (1:10 to 1:6)