Allyl Mercaptan → (2S,4R)-1-benzyl 2-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-1,2-dicarboxylate

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Reaction Steps

To a clear solution of (2S,4R)-1-benzyl 2-methyl 4-(biphenyl-4-yl)-4-hydroxypyrrolidine-1,2-dicarboxylate (3236 mg, 7.5 mmol) and prop-2-ene-1-thiol (834 mg, 9.00 mmol) in Acetonitrile (40 mL) was added Scandium(III) trifluoromethanesulfonate (369 mg, 0.750 mmol) as solid by one portion at room temperature. The formed pink solution was stirred at this temperature for 20 h. Quenched with sat. ammonium chloride, extracted with EtOAc. Washed the organic layer with brine, dried over MgSO4, filtered, evaporated in vacuo. The residue was purified by Biotage column, eluted with 5%˜50% EtOAc-Hexane to afford a mixture of diastereomers (2.88 g, 79%) and recovered starting material (0.600 g, 18%). This mixture was purified by Biotage column again, eluted with 2%˜8% EtOAc-Toluene to afford the desired product (2S,4R)-1-benzyl 2-methyl 4-(allylthio)-4-(biphenyl-4-yl)pyrrolidine-1,2-dicarboxylate (900 mg, 1.661 mmol, 22.15% yield) as an viscous oil and the undesired diastereomer plus some overlapped fraction (1.80 g) as an viscous oil. 1H NMR (500 MHz, CHLOROFORM-D) δ ppm 2.59-2.75 (m, 1 H), 2.77-2.93 (m, 3 H), 3.60 (s, 1.5 H), 3.77 (s, 1.5 H), 3.92 (d, J=11.60 Hz, 1 H), 4.20-4.30 (m, 1 H), 4.37-4.47 (m, 1 H), 4.92-5.34 (m, 4 H), 5.55-5.72 (m, 1 H), 7.20-7.65 (m, 14 H). LC-MS (retention time: 3.34 min, method B), MS m/z 488 (M+H).

Provenance & Evidence