Stereocontrolled introduction of an amino group at C-6 of d-galactose via (3,3)-sigmatropic rearrangements—novel synthesis of lincosamine and 7-epi-lincosamine precursors

A new and stereoselective route to the aminoglycoside components of the antibiotics lincomycin and clindamycin is presented. The key step involves diastereoselective introduction of the amino group at C-6 of d-galactose by (3,3)-sigmatropic rearrangements of the corresponding allylic (Z)-trifluoroacetimidate and (Z)- and (E)-allylic thiocyanates. Epoxidation of the resulting trifluoroacetamide with m-CPBA led to the epoxide with high threo-selectivity.