反应详情

(−)-1,2-Bis((2S,5S)-2,5-dimethylphospholano)ethane(cyclooctadiene)-rhodium(I)tetrafluoroborate (28.2 mg, 0.051 mmol) was added to a stirred solution of (Z)-methyl 2-(benzyloxycarbonylamino)-2-(2H-pyran-3(4H,5H,6H)-ylidene)acetate (310 mg, 1.015 mmol) in MeOH (10 mL) and the mixture was vacuum flushed with N2, followed by H2, and then the reaction was stirred under H2 (60 psi) at rt for 2 d. The reaction mixture was concentrated and the residue was purified by flash silica chromatography (loading solvent: DCM, eluted with 20% EtOAc in hexanes) to yield (S)-methyl 2-(benzyloxycarbonylamino)-2-((S)-tetrahydro-2H-pyran-3-yl)acetate (204 mg) as clear colorless oil. LC-MS retention time 1.437 min; m/z 307.89 (MH+). LC data was recorded on a Shimadzu LC-10AS liquid chromatograph equipped with a PHENOMENEX® Luna 10u C18 3.0×50 mm column using a SPD-10AV UV-Vis detector at a detector wave length of 220 nM. The elution conditions employed a flow rate of 4 mL/min, a gradient of 100% Solvent A/0% Solvent B to 0% Solvent A/100% Solvent B, a gradient time of 3 min, a hold time of 1 min, and an analysis time of 4 min where Solvent A was 5% MeOH/95% H2O/10 mM ammonium acetate and Solvent B was 5% H2O/95% MeOH/10 mM ammonium acetate. MS data was determined using a MICROMASS® Platform for LC in electrospray mode. 1H NMR (400 MHz, chloroform-d) δ ppm 7.30-7.46 (m, 5H), 5.32 (d, J=8.8 Hz, 1H), 5.12 (s, 2H), 4.36 (dd, J=8.9, 5.6 Hz, 1H), 3.84-3.98 (m, 2H), 3.77 (s, 3H), 3.28-3.37 (m, 1H), 3.23 (dd, J=11.3, 10.5 Hz, 1H), 2.04-2.16 (m, 1H), 1.61-1.75 (m, 3H), 1.31-1.43 (m, 1H).

1. customflushed with N2
2. concentrationThe reaction mixture was concentrated
3. customthe residue was purified by flash silica chromatography (loading solvent: DCM, eluted with 20% EtOAc in hexanes)