A TOTALLY SYNTHETIC ROUTE TO ENANTIOMERICALLY PURE D AND L-6-AMINO-6,8-DIDEOXYOCTOSES - STEREOCONTROLLED SYNTHESIS OF METHYL ALPHA-D-LINCOSAMINIDE

Methyl alpha-D-lincosaminide (25) has been synthesized from -isopropyl idene-1-(2-furyl)-2-aminobutane-1,3-diol (7). The key intermediate, me thyl tetradeoxy-alpha-D-ribo-oct-2-enopyranosid-4-ulose (11) was obtai ned in two steps from alcohol 7. Reduction of the ketone group at C-4 in the glycoside 11 with sodium borohydride-cerium chloride reagent, f ollowed by epoxidation of the C2=C3 double bond and subsequent scissio n of the oxirane ring led, with high stereo- and regioselectivity, to the N-benezenesulfonyl sugar 23. Treatment of the latter with sodium i n liquid ammonia yielded the tide compound.