Synthesis and absolute stereochemistry of (-)-protolichesterinic acid, antitumor antibiotic lactone from Cetraria islandica
摘要:
The first synthesis of (-)-protolichesterinic acid is described. The approach, based on a facially selective 2 + 2 cycloaddition reaction of dichloroketene with an enantiopure O-alkyl enol ether, permits the assignment of the absolute stereochemistry of the natural product to be made (2S,3R).
Synthesis and absolute stereochemistry of (-)-protolichesterinic acid, antitumor antibiotic lactone from Cetraria islandica
摘要:
The first synthesis of (-)-protolichesterinic acid is described. The approach, based on a facially selective 2 + 2 cycloaddition reaction of dichloroketene with an enantiopure O-alkyl enol ether, permits the assignment of the absolute stereochemistry of the natural product to be made (2S,3R).
Enantioselectivesyntheses of several paraconic acids have been achieved using catalyzed asymmetric hydrogenation of β-keto esters with SYNPHOS® as a ligand. This strategy allowed the short synthesis of biologically active (−)-methylenolactocin 1, (−)-protolichesterinic acid 2, (−)-phaseolinicacid 3 and (+)-roccellaric acid 4.