摘要:
                                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. (C) 1997 Elsevier Science Ltd.