Diisopropylethylamine → 4-Nitrophenyl 3-(tert-butyldiphenylsilanoxy)-2,2-dimethylpropylcarbamate

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Reaction Steps

To a solution, at 0° C., of 0.120 g (3.51 mmol) of 3-(tert-butyldiphenylsilanoxy)-2,2-dimethylpropylamine in 25 ml of dichloromethane are added dropwise 1.42 g (7.03 mmol) of 4-nitrophenyl chloroformate (CAS 7693-46-1) dissolved in 5 ml of dichloromethane. 0.63 ml (3.5 mmol) of diisopropylethylamine is then added. Stirring is continued at 0° C. for 45 minutes, and the temperature of the mixture is then allowed to return to 0° C. over 1 hour. 20 ml of saturated aqueous sodium hydrogen carbonate solution are then added. The organic phase is separated out on a hydrophobic filter cartridge and the solvent is partially evaporated off under reduced pressure to a volume of about 8 ml. This solution is chromatographed on a column of silica gel, eluting with a mixture of 5 to 40% ethyl acetate in cyclohexane, to give 0.21 g of 4-nitrophenyl 3-(tert-butyldiphenylsilanoxy)-2,2-dimethylpropylcarbamate in the form of an oil.

Provenance & Evidence