Trimethyl orthoformate → 1-Boc-3-(3-oxo-1-piperazinyl)azetidine

Participants

Reaction Steps

A mixture of piperazin-2-one (1.52 g, 15.1 mmol), 3-oxoazetidine-1-carboxylic acid tert-butyl ester (2.0 g, 11.6 mmol) and trimethyl orthoformate (12.8 mL, 12.4 g, 117 mmol) in AcOH (0.7 mL) and DCE (50 mL) was stirred for 5 h before the addition of triacetoxyborohydride (4.9 g, 23.2 mmol). The resulting mixture was stirred for 16 h then partitioned between DCM and H2O. The organic layer was dried (Na2SO4) and concentrated in vacuo. The resulting oil was purified by column chromatography (Si—PCC, MeOH:DCM, 0-10%) affording the title compound as a foam (827 mg, 28%). 1H NMR (CDCl3, 300 MHz): δ 6.24 (s, 1 H); 3.97 (dd, J=8.9, 7.1 Hz, 2 H); 3.82 (dd, J=5.2, 2.2 Hz, 2 H); 3.40 (td, J=5.2, 2.2 Hz, 2 H); 3.24-3.15 (m, 1 H); 3.07 (s, 2 H); 2.60 (t, J=5.4 Hz, 2 H); 1.44 (s, 9 H).

Provenance & Evidence