Kinetic separation methodology for the stereoselective synthesis of (E)- and (Z)-alpha-fluoro-alpha,beta-unsaturated esters via the palladium-catalyzed carboalkoxylation of 1-bromo-1-fluoroalkenes.
[reaction: see text] Methodology for the stereoselective preparation of both (E)- and (Z)-alpha-fluoro-alpha,beta-unsaturated esters is described. 1-Bromo-1-fluoroalkenes (E/Z approximate 1:1) can be isomerized to high E/Z ratio mixtures, which participate in palladium-catalyzed carboalkoxylation and lead to (Z)-alpha-fluoro-alpha,beta-unsaturated esters in high stereoselectivity. The same starting material can also be kinetically reduced to get an E/Z ratio of 0:100; similar carboalkoxylation reaction at 70 degrees C affords (E)-alpha-fluoro-alpha,beta-unsaturated esters stereospecifically.
Xu
Jianjun
J
Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA.
Burton
Donald J
DJ
D000475:Alkenes / Q000138:chemical synthesis / Q000737:chemistry; D002384:Catalysis; D004952:Esters / Q000138:chemical synthesis*; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry; D007700:Kinetics; D010165:Palladium; D013237:Stereoisomerism
D000475:Alkenes; D004952:Esters; D006845:Hydrocarbons, Fluorinated; D010165:Palladium