Dicyclohexylcarbodiimide → HCID 13984254, compound

Participants

Reaction Steps

A solution of 188.0 g (0.88 mol) of dicyclohexylcarbodiimide in 300 ml of THF was added dropwise, within 15 minutes, to a solution of 129.0 g (0.88 mol) of monomethyl (2R,2S)-2,3-oxirandicarboxylate and 196.0 g (0.8 mol) of t-butyl-N-(4-methoxyphenyl)glycinate [M. Shiozaki et al., Tetrahedron 40, 1795, (1984)] in 1100 ml of THF. The mixture was subsequently stirred for a further 30 minutes at room temperature, the resultant precipitate was separated off by filtration, and the filtrate solution was evaporated in vacuo. After purification of the product on 1.8 kg of silica gel (toluene:ethyl acetate=7:3), 263.2 g (90% of theory) of the title compound were obtained as crystals, melting point: 89° C. [α]D20 =-21.78° (c=0.435 in CHCl3). The enantiomer ratio, of 3:2, determined in the preparation example was confirmed by NMR-shift experiments using Eu(TFC)3.

Provenance & Evidence