Monobenzone → (R)-2-(4-Benzyloxy-phenoxymethyl)-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a 250 mL round bottomed flask which contained a suspension of NaH (1 g, 24 mmol) in DMF (100 mL) was added p-benzyloxy phenol (4 g, 20 mmol) at 0° C., The mixture was allowed to warm to rt and stir at rt for 30 min then cooled to 0° C. To this reaction mixture was added (R)-2-(toluene-4-sulfonyloxymethyl)-pyrrolidine-1-carboxylic acid tert-butyl ester (7.1 g, 20 mmol) at 0° C. The resulting mixture was allowed warm to rt and stir at rt for 30 min and then was heated to 95° C. for 5 h. After cooling to rt, the mixture was poured into 500 mL ice-water solution and this solution was allowed to stir at 0° C. for 30 min. The solid formed was filtered out, dried through air to provide the crude which was further purified by recrystallization with ether-hexane to afford the title product (5 g, 65%); LCMS; 100%, ESI+, Calcd: 383.49 m/z. Found: 284.4, (M+1-boc). 1H NMR (400 MHz, CDCl3); δ 1.47 (s, 9H), 1.79-2.10 (m, 4H), 3.26-3.45 (m, 2H), 3.66-3.91 (m, 1H), 4.01-4.19 (m 2H), 5.01 (s, 2H), 6.83-6.91 (m, 4H), 7.28-7.44 (m, 5H):

Provenance & Evidence