AbstractAn efficient method of preparing various terminal alkynes from 1,1‐dibromo‐1‐alkenes by using TBAF (tetra‐n‐butylammonium fluoride) as a base and triphenylphosphane as a reductant was developed. This method is strong base and low/high temperatures free, and can tolerate a broad range of substrates. These advantages were well demonstrated by the application of this method to the total synthesis of polyene natural product dihydroxerulin.magnified image
New stereoselective methodology for the synthesis of dihydroxerulin and xerulin, potent inhibitors of the biosynthesis of cholesterol
摘要:
A new stereoselective methodology for the synthesis of both dihydroxerulin and xerulin has been devised. The key step required cross-coupling reactions between the bromo trienyne, (1E,3E,5E)-l-bromo-8-trimethylsilyl-1,3,5-octatrien-7-yne and the appropriate conjugated diynes. The palladium-catalyzed tandem cross-coupling/cyclization reaction of the resulting polyenynes with (Z)-3-iodo-2-propenoic acid led directly to dihydroxerulin or xerulin with a high degree of stereoselectivity. (C) 2004 Elsevier Ltd. All rights reserved.