An efficient method to construct the A,B-rings component toward total syntheses of phycocyanobilin and its derivative as a photoprobe

Article abstract of DOI:10.1246/bcsj.73.497

Total syntheses of physocyanobilin and its derivative bearing a photoreactive group at the D-ring accomplished by developing a new and efficient method for the construction of A,B-rings component, which consists of the Wittig-type new coupling reaction of 4-(1-methoxyethyl or 1- tosylethyl)-3-methyl-5-tosyl-1,5-dihydro-2H-pyrrol-2-one and a 2-formyl pyrrole derivative in the presence of (n)Bu₃P and a base, followed by reduction with aluminum amalgam and a subsequent acid or base treatment.