3-Oxo-azetidine-1-carboxylic acid tert-butyl ester → [1,3′-Biazetidine]-1′-carboxylic acid, 3-hydroxy-, 1,1-dimethylethyl ester

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Reaction Steps

A 10 mL round-bottomed flask was charged with a solution of 3-oxoazetidine-1-carboxylic acid tert-butyl ester (0.52 g, 3.1 mmol), azetidin-3-ol hydrochloride (0.5 g, 4.6 mmol) and 4 Å molecular sieves (0.7 g) in DCE (8 mL). The reaction mixture was stirred for 7 h at room temperature. Sodium triacetoxyborohydride (1.3 g, 6.13 mmol) was added and the reaction mixture was stirred for 18 h at room temperature. The suspension was filtered through Celite and the filtrate was concentrated in vacuo. The residue was purified by flash chromatography (Si—PPC, MeOH:DCM, gradient 0:100 to 40:60) to give 3-Hydroxy-[1,3]biazetidinyl-1′-carboxylic acid tert-butyl ester as yellow oil (0.69 g, 99%). 1H NMR (CDCl3, 400 MHz) δ 4.45-4.35 (m, 1 H); 3.96 (dd, J=9.3, 6.7 Hz, 2 H); 3.74 (dd, J=9.3, 4.5 Hz, 2 H); 3.66 (td, J=8.8, 6.7 Hz, 2 H); 3.40-3.37 (m, 1 H); 3.20 (td, J=8.8, 4.5 Hz, 2 H); 1.43 (s, 9 H).

Provenance & Evidence