- Mild, efficient, and robust method for stereocomplementary iron-catalyzed cross-coupling using (E)- and (Z)-enol tosylates
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Iron-catalyzed cross-coupling of Grignard reagents (RMgX) with (E)- and (Z)-enol tosylates proceeded smoothly to give a variety of the corresponding (E)- and (Z)-trisubstituted ,-unsaturated methyl esters (total 30 examples; 55-98% yield). The simple, mild, stereoretentive method utilized iron(III) chloride (FeCl3), iron(III) acetylacetonate [Fe(acac)3], and iron(III) tris(dibenzylmethane) [Fe(dbm). The (E)- and (Z)-enol tosylates were readily prepared by the reported stereocomplementary tosylation method from methyl -keto esters or -formyl esters. Methyl -formyl esters were obtained via a practical and robust TiCl4-Et3N-mediated -formylation of methyl esters with methyl formate.
- Nishikado, Hiroshi,Nakatsuji, Hidefumi,Ueno, Kanako,Nagase, Ryohei,Tanabe, Yoo
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experimental part
p. 2087 - 2092
(2010/10/03)
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