Catalytic Z-selective olefin cross-metathesis for natural product synthesis

被引：0
作者：
Simon J. Meek
Robert V. O’Brien
Josep Llaveria
Richard R. Schrock
Amir H. Hoveyda
机构：
[1] Merkert Chemistry Center,Department of Chemistry
[2] Boston College,Department of Chemistry
[3] Massachusetts Institute of Technology,undefined
来源：
Nature | 2011年 / 471卷
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摘要：
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 Alzheimer’s disease, and the potent immunostimulant KRN7000.
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页码：461 / 466
页数：5
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