ADVANTAGES OF FLUOROFORMATES AS CARBOALKOXYLATING REAGENTS FOR POLAR REACTANTS

While chloroformates react explosively with DMSO and exothermically with DMF and other tertiary amides, we have found that fluoroformates are stable in these solvents below 100°C. Several important classes of hydroxyl-and amine-containing organic compounds are insoluble in aprotic solvents less polar than DMSO and DMF and thus cannot becarboalkoxylated in inert media with chloroformates. In this paper, we show that such compounds can be easily and efficiently carboalkoxylated with fluoroformates in DMSO or DMF (NMP). Examples include the per-carboalkoxylation of glucose, salicin, adonitol, sucrose, and thymidine in 77-89% yield. KF, or preferably triethylamine, is used as the proton scavenger. While cellulose is only partly carboalkoxylated under these conditions, essentially all of the OH functions in polyvinyl alcohol of average MW 12000 are converted to carbethoxy groups. © 1990, American Chemical Society. All rights reserved.