(3aS)-1-methyl-3,3-diphenyl-hexahydropyrrolo(1,2-c)(1,3,2)oxazaborole → HCID 10261627, compound

Participants

Reaction Steps

Borane dimethylsulfide complex (2.75 mL, 28.6 mmol) was added at room temperature to a stirred solution of (S)-2-methyl-CBS-oxazaborolidine (2.87 mL, 1M) in dry TXF (50 mL). The resulting solution was stirred at room temperature to 10 mins before a solution of 3-chloro-1-(2-thienyl)-1-propanone (2.5 g, 14.3 mmol) in dry THF (100 mL) was added dropwise over 1 hr. After complete addition the resulting solution was stirred at room temperature for a further 1 hr before the solvent was removed in vacuo. The residue was taken up in ether (200 mL) and washed with NH4Cl (sat, 100 mL). The organic phase was dried (MgSO4) and concentrated in vacuo. The residue was purified by flash chromatography eluting silica gel with hexane:ether [7:3] to yield a colourless oil (2.1 g, 84%); Optical purity determined by capillary electrophoresis to be 83% ee; δH (300 MHz, CDCl3) 7.25 (1H, d, Ar), 7.08-6.9 (2H, m, Ar), 5.28-5.20 (1H, m, CHO), 3.80-3.52 (2H, m, CH2), 2.35-2.12 (2H, m, CH2).

Provenance & Evidence