An expedient synthesis of racemic combretastatin and isocombretastatin

摘要

The stilbenoid constituents of Combretum caffrum possess pronounced antineoplastic and antimitotic activities.The most potent agents are R(-)combretastatin 1,and combretastatins A-1 to A-4.A novel and simple method for the synthesis of (+-)1 and isocombretastatin 5 in which an appropriately substitued 1,3-diarylpropanoid is transformed into a stibenoid is described.The key step involves the alkali induced rearrangement of chalcone epoxide 9 to #alpha#-hydroxy acid 10 and that is followed by oxidative decarboxylation and reduction.