Enzymatic procedure catalysed by lipase from Candida antarctica for the regioprotection-deprotection of glucosamine

Both peracetyl alpha-glucosamine 3 and its beta-epimer 4 undergo alcoholysis with butanol in THF catalysed by lipase from Candida antarctica (Novozym 435) to afford the triester 6 and diester 9, respectively. Esterification of these compounds, using vinyl acetate in the presence of Novozym 435, gives the partial esters 10 and 11, bearing a deprotected hydroxyl function at C-4, ready for inversion of configuration to open a route in the preparation of galactosamine. (C) 1999 Elsevier Science Ltd. All rights reserved.