1300026-45-2Relevant academic research and scientific papers
Catalytic Z-selective olefin cross-metathesis for natural product synthesis
Meek, Simon J.,Obrien, Robert V.,Llaveria, Josep,Schrock, Richard R.,Hoveyda, Amir H.
experimental part, p. 461 - 466 (2012/04/10)
Alkenes are found in many biologically active molecules, and there are a large number of chemical transformations in which alkenes act as the reactants or products (or both) of the reaction. Many alkenes exist as either the E or the higher-energy Z stereoisomer. Catalytic procedures for the stereoselective formation of alkenes are valuable, yet methods enabling the synthesis of 1,2-disubstituted Z alkenes are scarce. Here we report catalytic Z-selective cross-metathesis reactions of terminal enol ethers, which have not been reported previously, and of allylic amides, used until now only in E-selective processes. The corresponding disubstituted alkenes are formed in up to >98% Z selectivity and 97% yield. These transformations, promoted by catalysts that contain the highly abundant and inexpensive metal molybdenum, are amenable to gram-scale operations. Use of reduced pressure is introduced as a simple and effective strategy for achieving high stereoselectivity. The utility of this method is demonstrated by its use in syntheses of an anti-oxidant plasmalogen phospholipid, found in electrically active tissues and implicated in Alzheimers disease, and the potent immunostimulant KRN7000.
EFFICIENT METHODS FOR Z- OR CIS-SELECTIVE CROSS-METATHESIS
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Page/Page column 58; 63, (2011/09/14)
The present invention generally relates to methods for performing metathesis reactions, including cross-metathesis reactions. Methods described herein exhibit enhanced activity and stereoselectivity, relative to known methods, and are useful in the synthe
