Imidazole → 3-(tert-Butyldimethylsilanyloxy)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution containing 3-hydroxypyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (2, 14.8 g, 60 mmol) in DCM (150 mL) was cooled to 0° C. To this solution was added imidazole (5.4 g, 79 mmol) followed by t-butyl-dimethylsilyl-chloride (10 g, 66 mmol) in two portions. The reaction mixture was warmed to ambient temperature over 1 h. After 5 h, the reaction mixture was diluted with 1M HCl and extracted twice with DCM. The combined organic extracts were dried over anhydrous Na2SO4, filtered, and concentrated to afford 21.2 g (99%) of 3-(tert-butyldimethylsilanyloxy)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (3) as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ4.38-4.34 (m, 1H), 4.18 (br s, rotomers, 0.5H), 4.04 (app d, J=2.1 Hz, rotomers, 0.5H), 3.74 (s, 3H), 3.62-3.50 (m, 2H), 2.04-1.96 (m, 1H), 1.85-1.78 (m, 1H), 1.46 (s, minor rotomer), 1.41 (s, 9H), 0.92 (s, minor rotomer), 0.86 (s, 9H), 0.11 (s, 6H), 0.09 (s, minor rotomer) ppm.

Provenance & Evidence