STEREOCHEMISTRY OF DIAMINATION OF (E)-2-BUTENES AND (Z)-2-BUTENES - CRYSTAL AND MOLECULAR-STRUCTURES OF MESO-2,3-DIAMINOBUTANE AND DL-2,3-DIAMINOBUTANE DITOSYLATES

Stereospecific anti-addition of diethyl N,N-dibromophosphoramidate (DB PA) to (E)- and (Z)-2-butenes was definitely corroborated by X-ray str uctural determinations of threo- and erythro-2-amino-3-bromobutane hyd rochlorides prepared from the corresponding adducts without changing t he configuration on either chiral centers. The stereochemistry of azid ation of threo- and erythro-2-amino-3-bromobutane hydrochlorides leadi ng to dl- and meso-2,3-diaminobutane ditosylates respectively (after r eduction of an azide function) was deduced from an X-ray crystallograp hic analysis of these diamine salts. The X-ray crystallographic analys is was carried out for three compounds: two reaction products and subs trate (Scheme 2).