Trifluoroacetic acid → HCID 71273704, compound

Participants

Reaction Conditions

Reaction Steps

tert-Butyl(9aS)-3-hydroxy-3-(1-oxo-3,4-dihydro-1H-isochromen-6-yl)hexahydropyrazino[2,1-c][1,4]oxazine-8(1H)-carboxylate (1.84 g, 4.55 mmol) was diluted with TFA (18 mL, 234 mmol) and cooled to 0° C. Some off gassing was apparent and after a few minutes a homogenous solution had been formed. Approximately 5 minutes post-TFA addition, Et3SiH (5.09 mL, 31.8 mmol) was added and the reaction mixture allowed to slowly warm to RT (allowed to warm naturally in the ice bath) where it was stirred for 18 h. The trans:cis diastereomeric ratio appeared to be ˜95:5. The reaction vessel was transferred to a rotary evaporator and concentrated in vacuo to a two phase liquid. This crude material was diluted with CH2Cl2 washed with NaHCO3, aq then water. The separately kept aqueous layers were subsequently extracted once with the same portion of CH2Cl2, the combined organics dried with MgSO4, filtered and concentrated in vacuo. The crude residue was dried under house vacuum then the mixture was further purified by flash chromatography (2% MeOH 2% Et3N in CH2Cl2) to afford the title compound.

Provenance & Evidence