4-Methylmorpholine → tert-butyl 4-(2-{hydroxy-[3-(3-methoxypropyl)-1-methyl-1H-indol-5-yl]methyl}-3-methylbutyl)-2,2-dimethyloxazolidine-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of 12.51 ml of dibutylmagnesium (1M in heptane) in 70 ml of tetrahydrofuran is cooled to 0° C. and admixed with 7.80 ml of n-butyllithium (1M in hexane). After 10 minutes, the mixture is admixed with a solution of 3.60 g of 5-bromo-3-(3-methoxypropyl)-1-methyl-1H-indole (residue 3) and 0.14 ml of N-methylmorpholine in 15 ml of tetrahydrofuran and stirred at 0° C. for 30 minutes. The reaction mixture is cooled to −78° C. and admixed with the solution of 3.02 g of tert-butyl 4-(2-formyl-3-methylbutyl)-2,2-dimethyloxazolidine -3-carboxylate in 15 ml of tetrahydrofuran over 2 minutes. The resulting mixture is stirred at −78° C. for another 45 minutes and subsequently successively quenched with 1M ammonium chloride solution, diluted with water and extracted with tert-butyl methyl ether (3×). The combined organic phases are washed successively with 0.5N HCl (cold)(2×), water and brine, dried over sodium sulphate and filtered, and the filtrate is concentrated by evaporation. The title compound (diastereomer mixture) is obtained as a white foam from the residue by means of flash chromatography (SiO2 60F). Rf=0.21 (1:2 EtOAc-heptane). Rt=24.2/25.4 (gradient II).

Provenance & Evidence