A novel stereoselective carbon-chain extension reaction at the C-6 position of 1,6-anhydropyranose

6-Bromo-1,6-anhydro-d-mannose triacetate reacted with a variety of carbon nucleophiles such as allylsilane, silylacetylenes, propargylsilane, and aromatic compounds in the presence of silver triflate to give the corresponding chain extended products at C-6 in high exo-selectivities. The product obtained from the reaction with propargylsilane was efficiently transformed into a naturally occurring heptopyranose derivative found in bacterial lipopolysaccharide.