[Synthesis of the capsular polysaccharide of Streptococcus pneumoniae type 14. 1. Synthesis of a derivative of the tetrasaccharide repetitive link].

A branched tetrasaccharide derivative of the repeating unit of the capsular polysaccharide of Streptococcus pneumoniae type 14 has been synthesised by condensation of per-O-benzoylated 1,2-O-(1-cyano)ethylidene derivative of lactose with 6-O-tritylated methyl lactosaminide.