A stereoselective total synthesis of (+)-cladospolide A from D-ribose is described. Key features of the synthesis include olefin cross metathesis and Yamaguchi lactonization.
Intramolecular Michael Addition of N- and O-Centred Nucleophiles to Tethered Acrylates. The Role of Double-Bond Geometry in Controlling the Diastereo- selectivity of Cyclizations Leading to 2,6-Disubstituted Tetrahydropyrans and Piperidines.
Dynamickineticasymmetrictransformation (DYKAT) of 1,5-diols via combined lipase and ruthenium catalysis provides enantiomerically pure diacetates in high diastereoselectivity, which can serve as intermediates in natural product synthesis. This is demonstrated by the synthesis of (+)-Solenopsin A.
Aryne Acyl-Alkylation in the General and Convergent Synthesis of Benzannulated Macrolactone Natural Products: An Enantioselective Synthesis of (−)-Curvularin
作者:Pamela M. Tadross、Scott C. Virgil、Brian M. Stoltz
DOI:10.1021/ol100335y
日期:2010.4.2
A general approach for the synthesis of benzannulated macrolactone natural products utilizing an aryne acyl-alkylation reaction is described. Toward this end, the total syntheses of the natural products (−)-curvularin, curvulin, and (−)-diplodialide C are reported. Furthermore, the aryne insertion technology has enabled the rapid conversion of simple diplodialide natural products to curvularin, thereby
Formal Synthesis of (+)-Brefeldin A: Application of a Zinc-Mediated Ring Expansion Reaction
作者:Weimin Lin、Charles K. Zercher
DOI:10.1021/jo0701379
日期:2007.6.1
formal synthesis of (+)-brefeldin A was accomplished through a synthetic approach that relied upon three keys steps. The five-membered ring was generated in a stereocontrolled fashion through application of a tandem conjugate addition-intramolecular cyclization method developed by Toru. Ring-closingmetathesis provided access to a twelve-membered β-keto lactone, which was ring-expanded to the α,β-unsaturated-γ-keto
Synthesis and stereochemical assignment of (+)-Cladospolide D
作者:Ke-Jhen Lu、Chia-Hsiu Chen、Duen-Ren Hou
DOI:10.1016/j.tet.2008.10.059
日期:2009.1
Cladospolides A-D are 12-membered, alpha,beta-unsaturated lactones isolated from various species of Cladosporium. Cladospolide D is unique in its gamma-keto functionality and possesses antifungal activity; however, the stereochemistry of Cladoapolide D was unknown. We report the asymmetric syntheses to generate both possible diastereomers of Cladospolide D. Two regioselective cross-metatheses were applied to form the carbon skeleton, and the two olefins were differentiated by Michael addition, hydrogenation, and elimination. Later, the macrocycle was achieved through the Yamaguchi protocol. After comparing the spectroscopic data of the synthetic Cladospolide D with the reported values, the stereochemistry of Cladospolide D is confirmed as (2E,5R,11S). (C) 2008 Elsevier Ltd. All rights reserved.