A simple route to 4-substituted-3,4-didehydroprolines, mechanistic probes for the inhibition of prolyl-4-hydroxylase

Article abstract of DOI:10.1016/S0040-4039(97)01182-9

Treatment of the 9-phenylfluoren-9-yl (Pf) protected 4-oxo-proline-ethyl ester (6) with NaHMDS and N-(5-chloro-2-pyridyl)triflimide gives the corresponding enoltriflate in good yield. Pd mediated coupling of the triflate with trimethylalkyltin, trimethylaryltin, trimethylalkenyltin and carbon monoxide proceeds to give the 4-substituted-3,4-didehydroprolines.