Optically pure d-(+)-N-methylfucosamine (8) has been synthesized from a TBDMS-protected methyl l-serinate benzophenone Schiff base (O'Donnell's Schiff base, 1) in seven steps in 13% overall yield; Efficient construction of the requisite amino triol acetate 3a with the proper stereochemical configuration is accomplished in two steps with a chelation-controlled reduction-alkylation reaction using Bu2AlH·Al-iBu3/E-LiCH=CHCH3, followed by oxidation with OsO4. Conversion of the Schiff base to the N-benzhydryl protecting group and methylation (Eschweiler-Clark) is accomplished in one pot with NaCNBH3 in the presence of H2C=O. Deprotection and oxidation of the primary alcohol, followed by deacetylation with KCN, provided the desired product 8.
ASJC Scopus subject areas
- Organic Chemistry