Borane → HCID 86614039, compound

Participants

Reaction Steps

To a solution of (1S,2R,4aS,5R,8R,8aR)-2-(acetyloxy)-8a-hydroxy-3,8-dimethyl-5-(1-methylethenyl)-1,2,4a,5,6,7,8,8a-octahydronaphthalen-1-yl (2S,3aR,9bR)-6-chloro-9b -hydroxy-5-methyl-1,2,3,3a,5,9b-hexahydropyrrolo[2,3-c][2,1]benzoxazine-2-carboxylate (Preparation 1, 500 mg, 0.89 mmol) in tetrahydrofuran (8 ml) at −10° C. under nitrogen was added borane (1M solution in tetrahydrofuran, 2 ml, 2 mmol) and the resulting mixture stirred and allowed to come to room temperature. After 5 hours borane (1M solution in tetrahydrofuran, 1 ml, 1 mmol) was added and the reaction stirred at room temperature for 18 h. To the reaction mixture was added 4-methylmorpholine N-oxide (600 mg, 5.1 mmol) and the mixture heated to gentle reflux for 3 hours. The reaction mixture was concentrated in vacuo and the residue treated with water (30 ml) and extracted with ethyl acetate (2×30 ml). The combined organic extracts were washed with saturated aqueous sodium chloride solution, dried (MgSO4) and the solvent removed in vacuo to give an orange glass. The crude product was purified by column chromatography on silica eluting with hexane:ethyl acetate (2:1 then 1:1) and then ethyl acetate. The pure fractions were combined and concentrated in vacuo to give a the title product as a yellow solid (132 mg, 26%).

Provenance & Evidence