No abstract

A convenient method for synthesis of 2R,3S and 2S,3S N-Boc phenylalanine epoxides using readily available allylamine is described. Previous methods employed multistep synthetic routes from l-phenyl alanine that include use of m-chloroperbenzoic acid (m-CPBA) and a chromatographic method for purification of the desired diastereomers. Column purification could be eliminated by bringing in much improvement in the existing process. The process was further enhanced by replacing m-CPBA with oxone, an ecofriendly reagent advantageous for commercial application. The overall green process discussed involves the recovery and recycling of enantiomers of chiral allyl amines and judicial separation of diastereomers of the epoxides using simple economical methods.

There are several known processes for manufacturing the commercially important anaesthetic desflurane (CF 3 CHFOCHF 2 ) by the catalyzed reaction of commercially available isoflurane (CF 3 CHClOCHF 2 ) with hydrogen fluoride. The present available methods have the disadvantage of high catalyst usage, with consequent environmental problems, or of having to trade off low conversion against low selectivity. An alternative catalyst system was therefore sought that would avoid these problems, but would still give the benefits of a vapor-phase process and, in particular, a long catalyst life. A catalyst consisting of antimony pentafluoride supported on activated carbon has now been found to provide the basis for a novel vapor-phase process for the fluorination of isoflurane to desflurane using hydrogen fluoride. The process operates with a long catalyst life, high conversion, and high selectivity.

A convenient one step synthesis of chlorotrifluoroalkyl olefins starting from aldehydes was developed.