Diethyl Ether → (2S)-Methyl-1-(1,2-dioxo-3,3-dimethylpentyl)-azetidine-2-carboxylate

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Reaction Conditions

Reaction Steps

To a cooled (about −78° C.) solution of (2S)-Methyl-1-(1,2-dioxo-2-methoxyethyl)-azetidine-2-carboxylate from Reference Example 2 (0.98 g, 4.86 mmol, 1.0 eq) in dry tetrahydrofuran (15 mL) under an argon atmosphere was added 1,1-dimethylpropylmagnesium chloride in THF (6.30 mL of 1M solution, 6.30 mmol, 1.3 eq) over about 15 minutes. After stirring the resulting homogeneous mixture at about −78° C. for about 3 hours, the mixture was poured into chilled saturated ammonium chloride and extracted into ethyl acetate (2×50 mL). The organic phase was washed with water, dried over sodium sulfate and concentrated. Flash chromatography of the residue (2:3 ether:pentane) produced 0.90 g (77% yield) of the product as a colorless oil. 1H NMR (CDCl3) δ 0.77-0.98 (m, 3H); 1.20-1.30 (series of s, 6H); 1.68-2.01 (m, 2H); 2.24-2.40 (m, 1H); 2.60-2.80 (m, 1H); 3.80-3.82 (series of s, 3H); 3.99-4.43 (series of m, 2H); 4.84 and 5.26 (series of dd, 1H, J=6.9, 9.4).

Provenance & Evidence