THE INVENTION OF RADICAL REACTIONS PART XVIII. A CONVENIENT SOLUTION TO THE 1-CARBON PROBLEM (R-CO2H --> R-13CO2H)

Article abstract of DOI:10.1016/S0040-4020(01)85980-9

Radicals generated by photolysis (W light) of esters derived from N-hydroxy-2-thiopyridone react with electrophilic isocyanides 2a and (in the presence of trifluoroacetic acid) 2b to give adducts of type 3.Convenient reaction procedures have been worked out to hydrolyse the adducts to amides of type 5, from which the original acid can be regenerated under mild conditions.The three important acids oleic, linoleic and arachidonic have all given smooth reactions.In suitable examples, quantitative evolution of carbon dioxide and incorporation of ¹³C without dilution have been demonstrated.This reaction sequence will be useful for the labelling in the carboxyl group of prostaglandins, leukotrienes, and the side chain carboxyls of peptides.