Fluoroamines via Chiral Cyclic Sulfamidates

Abstract N-benzyl [1,2,3]-oxathiazolidine 2,2-dioxides (cyclic sulfamidates) were synthesized from their corresponding β-amino alcohols and used as substrates in fluorination reactions with tetrabutylammonium fluoride (TBAF). After desulfonation of the intermediates, the N-benzyl fluoroamines were debenzylated by transfer hydrogenolysis with Pd/C to yield (S) and (R)-2-amino-1-fluoropropanes (2B and 3B, respectively, both with 95% ee). The reactions were carried out on multi-gram scale without the need for chromatographic purification of the intermediates. In the presence of carbonate, the (S)- and (R)-N-benzylfluoroamines underwent intramolecular cyclizations in which fluoride was displaced to yield cyclic carbamates 13 and 14.