A series of novel benzoxepins 6 was designed and prepared as rigid-isoCA-4 analogs according to a convergent strategy using the coupling of N-tosylhydrazones with aryl iodides under palladium catalysis. The most potent compound 6b, having the greatest resemblance to CA-4 and isoCA-4 displayed antiproliferative activity at nanomolar concentrations against various cancer cell lines and inhibited tubulin
Synthesis of Bridged Medium-Sized Rings through the Intramolecular Pauson−Khand Reaction
作者:Carl J. Lovely、Hemalatha Seshadri、Brian R. Wayland、A. Wallace Cordes
DOI:10.1021/ol016308s
日期:2001.8.9
[GRAPHICS]A series of aromatic enynes containing steric buttressing elements were prepared and evaluated in the NMO-mediated Pauson-Khand cyclization. O-Allyl systems led to the expected angularly fused products, whereas the O-butenyl and O-pentenyl derivatives afforded the unprecedented bridge systems.
Synthesis of aromatic natural product frameworks using enyne metathesis
Enynes, easily obtained by the Sonogashira coupling reactions of aromatic iodides. undergo. with good yields, en ne metathesis using the Grubbs catalyst. The resulting dienes are interesting carbo- and heterocycles which can give complex natural frameworks by Diels Alder reactions. Thus. an estradiol type skeleton is obtained in two steps from the corresponding enynes. An example of a metathesis-Diels-Alder cascade one-pot process is reported. (C) 2001 Elsevier Science Ltd. All rights reserved.
Tandem Enyne Metathesis-Diels−Alder Reaction for Construction of Natural Product Frameworks
Enynes connected through aromatic rings are used as substrates for metathesis reactions. The reactivity of three ruthenium carbene complexes is compared. The resulting 1,3-dienes are suitable precursors of polycyclic structures via a Diels−Alder process. Some domino RCM-Diels−Alder reactions are performed, suggesting a possible beneficial effect of the ruthenium catalyst in the cycloaddition process