Pauson-Khand reactions are carried out with different substituted aromatic enynes yielding tricyclic cyclopentenones related to natural products. Reaction is promoted by dissolved Me3NO. Isomerization of the double bond of the cyclopentenone is observed except for compound 2e, with a non terminal triple bond.
Pauson-Khandreactions are carried out with different substituted aromatic enynes, yielding tricyclic cyclopentenones related to natural products such as chromenes. Enynes are easily obtained in a two-step approximation from the corresponding salicylaldehydes. The reaction is promoted by dissolved TMANO (trimethylamine N-oxide) and/or 4 A molecular sieves. This new way of induction for the Pauson-Khand
experimental conditions have been developed for an efficient catalyticPauson–Khandreaction. These are based on the use of a mixture of molecular sieves and tert-butanol as inducers of the process. This mixture, with the appearance of a paste, is able to adsorb CO, thus improving the conversion and making it possible to effect the reactions in the absence of a CO atmosphere. The protocol is applied
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.