3,4-Diamino-3,4-Diamino-3,4-dideoxy-L-chiro-inositol has been prepared from bromobenzene by a chemoenzymatic approach. The key chemical step was a tetrabutylammonium fluoride (TBAF) catalyzed vinyl aziridine opening employing p-toluenesulfonamide as a nucleophile, establishing the 1,2-trans relationship of the amino groups. (C) 2001 Elsevier Science Ltd. All rights reserved.