Tetrapyrroles. III. Homochiral dihydropyrromethenones from N-aminopyrroles and acetylenic acids

Article abstract of DOI:10.1016/S0040-4039(00)60940-1

Dihydropyrromethenone 29, a potential precursor for the synthesis of Phytochrome (8), Phycocyanin (9) and Phycoerythrin (10), has been prepared in homochiral form from pyrrolohydrazide 27 by a sequence involving F-induced 5-exo-dig cyclization to afford enamide 28, followed by photochemical 3,5-sigmatropic rearrangement.