A convergent synthesis of the marine cyclodepsipeptide (+)-jasplakinolide has been realized. The synthesis of the required (R)-beta-tyrosine unit is accomplished via the stereospecific palladium-catalyzed arylation of an enantiomerically pure dihydropyrimidinone. The overall yield of the synthesis, based on the longest linear sequence, is 6.6%.
A convergent synthesis of the marine cyclodepsipeptide (+)-jasplakinolide has been realized. The synthesis of the required (R)-beta-tyrosine unit is accomplished via the stereospecific palladium-catalyzed arylation of an enantiomerically pure dihydropyrimidinone. The overall yield of the synthesis, based on the longest linear sequence, is 6.6%.
l-N-Formyl tryptophan methyl ester (3) underwent a Bischler–Napieralskireaction with POCl3 at room temperature or under microwave irradiation, resulting in the unusual formation of β-carboline dimers 5 and 6. Most importantly, acetylation using Ac2O of each of the dimers 5 and 6 separately afforded 1-[3′-carbomethoxy-β-carbolinyl]-3-carbomethoxy-9-acetyl-β-carboline (7) as the only product, the structure