Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → Phenylmethyl 3,3-dimethyl-2-(methyloxy)-1-pyrrolidinecarboxylate

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Reaction Conditions

Reaction Steps

In a 500 ml flask was dissolved phenylmethyl 2-hydroxy-3,3-dimethyl-1-pyrrolidinecarboxylate (0.0475 mol, 11.8 g) in 100 ml methanol. Catalytic Pyridinium p-toluenesulfonate (0.00475 mol, 1.19 g) was added and the reaction was stirred at 20° C. for 45 min. The reaction was quenched with triethylamine (3 ml) and concentrated. The resulting crude oil was purified on 120 g silica (chloroform/ethyl acetate) yielding 11.2 g (90%) of phenylmethyl 3,3-dimethyl-2-(methyloxy)-1-pyrrolidinecarboxylate as a clear oil. LCMS (ESI+)=286 m/z (MNa+). 1H NMR (400 MHz, CDCl3)— rotomers δ 7.39-7.32 (m, 5H), 5.24-5.13 (m, 2H), 4.68 and 4.57 (s, 1H), 3.52-3.46 (m, 4H), 3.31 (s, 2H), 1.97-1.90 (m, 1H), 1.58-1.54 (m, 1H), 1.10 (s, 3H), 0.9 (s, 3H).

Provenance & Evidence