Tetrahedron letters

Boc-protected 1-(3-oxocycloalkyl) ureas via a one-step Curtius rearrangement: mechanism and scope

X Sun, R Rai, JR Deschamps, AD MacKerell, AI Faden…

Index: Sun, Xianyu; Rai, Rachita; Deschamps, Jeffrey R.; Mackerell Jr., Alexander D.; Faden, Alan I.; Xue, Fengtian Tetrahedron Letters, 2014 , vol. 55, # 4 p. 842 - 844

Full Text: HTML

Citation Number: 5

Abstract

Abstract 1-(3-Oxocyclobutyl) carboxylic acid (4a) was converted into N-Boc-protected 1-(3- oxocyclobutyl) urea (5a), a key intermediate for the preparation of agonists of metabotropic glutamate receptor 5, in one-step when treated with diphenyl phosphoryl azide and triethylamine in tert-butanol. The mechanism of the reaction involves a nucleophilic addition of the in situ generated tert-butyl carbamate to the isocyanate intermediate. This reaction ...