AN EFFICIENT SYNTHESIS OF L)-ALPHA-L-RHAMNOPYRANOSYL]OXYDECANOYL)OXYDECANOIC ACID, A RHAMNOLIPID FROM PSEUDOMONAS-AERUGINOSA

N-iodosuccinimide/triflic acid mediated one-pot two-step glycosylation of ethyl 2,3,4-tri-O-benzyl-1-thio-alpha-L-rhamnopyranoside (8) with phenyl 3,4-O-(2,3-dimethoxybutane-2,3-diyl)-1 -thio-alpha-L-rhamnopyra noside (10b) and phenacyl (R)-3- hydroxydecanoate (13) gave rhamnolipi d 17. The latter was transformed in five steps into the title compound 2. Esterification of 2 with diazomethane resulted into the correspond ing methyl ester derivative 1.