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