2-diazo-3,3,3-trifluoropropionyl chloride: reagent for photoaffinity labeling.

2-Diazo-3,3,3-trifluoropropionyl chloride has been synthesized from trifluorodiazoethane and phosgene. Its derivatives are acid stable, can be used to label enzymes, and undergo photolysis with substantially less rearrangement than do derivatives of other known diazoacyl reagents designed for photoaffinity labeling. In particular, the diazotrifluoropropionyl thioester of methyl N-acetylcysteine undergoes photolysis in methanol with about 40% insertion into the - OH bond of the solvent; by contrast, photolysis of other diazoacyl thioesters gives substantially quantitative Wolff rearrangement. The trifluoro compounds hold promise for the photoaffinity labeling of thiols.