Total Synthesis of the Potent Antitumor Polyketide (−)-Callystatin A
作者:Luiz C. Dias、Paulo R. R. Meira
DOI:10.1021/jo050352u
日期:2005.6.1
A highly convergent and efficient totalsynthesis of the potentantitumor polyketide (−)-callystatin A is described. The synthesis required 19 steps from N-propionyl oxazolidinone 23 and produced the desired product in 3.5% overall yield.
Males of the giant white butterfly Idea leuconoe release a complex mixture of compounds during courtship. Besides alkaloids, aromatics, terpenoids and hydrocarbons, several lactones have been identified in the pheromone bouquet. Two simple stereoselective methods to create the lactones in good enantiomeric excesses have been developed. The generation of the stereocenters of the beta-lactones 1a and 1b is based on a controlled C-C coupling by a Horner-Wadsworth-Emmons approach, followed by asymmetric dihydroxylation, whereas the synthesis of the delta-lactone 3b uses an enantioselective hydrogenation of a dioxoalkanoate precursor. The absolute configurations of the natural lactones 1a, 1b and 3b were determined by gas chromatography on a chiral stationary phase. Both 1a and 1b are of (S,S) configuration, suggesting their biosynthetic origin from (-)-viridifloric acid (7a) or (-)norviridifloric acid (7b), respectively. In contrast, natural 3b is a mixture of all enantiomers, in which the (5S,7S) enantiomer dominates.
A BUILDING BLOCK FORMING A C=C DOUBLE BOND UPON REACTION
申请人:Nuevolution A/S
公开号:EP1487848A2
公开(公告)日:2004-12-22
[EN] A BUILDING BLOCK FORMING A C=C DOUBLE BOND UPON REACTION<br/>[FR] ELEMENT CONSTITUTIF FORMANT UNE DOUBLE LIAISON C=C LORS DE LA REACTION
申请人:NUEVOLUTION AS
公开号:WO2003078445A2
公开(公告)日:2003-09-25
A building block having the dual capabilities of recognising an encoding element and transferring a Functional Entity Precursor to a recipient reactive group is disclosed. The building block may be used in the generation of a single complex or libraries of different complexes, wherein the complex comprises an encoded molecule linked to an encoding element. Libraries of complexes are useful in the quest for pharmaceutically active compounds.