Palladium-catalyzed desulfitative Mizoroki-Heck couplings of sulfonyl chlorides with mono- and disubstituted olefins: Rhodium-catalyzed desulfitative heck-type reactions under phosphine- and base-free conditions
New conditions have been found for the desulfitative Mizoroki-Heck arylation and trifluoromethylation of mono- and disubustituted olefins with arenesulfonyl and trifluoromethanesulfonyl chlorides. Thus (E)1,2-disubstituted alkenes with high stereoselectivity and 1,1,2-disubstituted alkenes with 12:1 to 21:1 E/Z steroselectivity can be obtained. Herrmann's palladacycle at 0.1 mol % is sufficient to catalyze these reactions, for which electron-rich or electron-poor sulfonyl chlorides and alkenes are suitable. If phosphine- and base-free conditions are required, 1 mol % [RhCl(C2H4)(2)] catalyzes the desulfitative cross-coupling reactions. Contrary to results reported for [RUCl2 (PPh3)(2)]-catalyzed coupling reactions with sulfonyl chlorides, the palladium and rhodium desulfitative Mizoroki-Heck coupling reactions are not inhibited by radical scavenging agents. Possible sulfones arising from the sulfonylation of alkenes at 60 degrees C are not desulfitated at higher temperatures in the presence of the Pd or Rh catalysts.
Keywords: alkenes Mizoroki-Heck reaction ; palladium ; phase-transfer catalysis ; rhodium ; Ruthenium(ii) complex ; aryl chlorides ; arylsulfonyl chlorides ; c-c ; alkenesulfonyl chlorides ; coordination chemistry ; cross-couplings ; aroyl chlorides ; vinylation ; arylation ; aroyl chlorides
Ecole Polytech Fed Lausanne, BCH, Lab Glychochem & Asymmetr Synth, CH-1015 Lausanne, Switzerland.
Record created on 2005-11-09, modified on 2016-08-08