A highly stereoselective synthesis of 1-amino-2,5-anhydro-1-deoxyhexitols via 2-trifluoromethyl-oxazolinium intermediates11Dedicated to Professor Hans Paulsen on the occasion of his 75th birthday.22Part of J.C. Norrild, “Reactivity of aminodeoxyalditols and derivaties in hydrogen fluoride”, Ph.D. Thesis, The Technical University of Denmark, 1996.

A series of 1-amino-2,5-anhydro-1-deoxyalditols, namely derivatives of 1-amino-2,5-anhydro-1-deoxy-D-glucitol, -D-mannitol and -D-talitol was prepared from the corresponding 1-deoxy-1-trifluoroacetamidohexitols by treatment with anhydrous hydrogen fluoride. The reaction was also performed on 1,3-dideoxy-1-trifluoroacetamido-D-ribo-hexitol and 1-deoxy-1-trifluoroacetamido-L-rhamnitol which both gave the expected C-2 inverted anhydrides. The reaction mechanism involves 2-trifluoromethyl-oxazolinium intermediates, which further undergo intramolecular attack of HO-5 at C-2 with inversion of the configuration. The reaction is stereospecific and highly regioselective. The crystal structure of 1-amino-2,5-anhydro-1-deoxy-D-glucitol hydrochloride is presented. (C) 1997 Elsevier Science Ltd.