Mechanistic analysis of an asymmetric palladium-catalyzed conjugate addition of arylboronic acids to β-substituted cyclic enones
نویسندگان
چکیده
An asymmetric palladium-catalyzed conjugate addition reaction of arylboronic acids to enone substrates was investigated mechanistically. Desorption electrospray ionization coupled to mass spectrometry was used to identify intermediates of the catalytic cycle and delineate differences in substrate reactivity. Our findings provide evidence for the catalytic cycle proceeding through formation of an arylpalladium(II) cation, subsequent formation of an arylpalladium–enone complex, and, ultimately, formation of the new C–C bond. Reaction monitoring in both positive and negative ion modes revealed that 4iodophenylboronic acid formed a relatively stable trimeric species under the reaction conditions.
منابع مشابه
Enantioselective palladium catalyzed conjugate additions of ortho-substituted arylboronic acids to β,β-disubstituted cyclic enones: total synthesis of herbertenediol, enokipodin A and enokipodin B.
The palladium-catalyzed conjugate addition (Michael addition) of ortho-substituted arylboronic acids to β,β-disubstituted cyclic enones, in particular 3-methyl cyclopent-2-enone and 3-methyl cyclohex-2-enone, is reported. With an achiral bipyridine-based palladium catalyst, good yields are obtained with a variety of ortho-substituted arylboronic acids. In the asymmetric version, good to very hi...
متن کاملMechanistic analysis of an asymmetric palladium-catalyzed conjugate addition of arylboronic acids to β-substituted cyclic enones† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc03337j Click here for additional data file.
An asymmetric palladium-catalyzed conjugate addition reaction of arylboronic acids to enone substrates was investigated mechanistically. Desorption electrospray ionization coupled to mass spectrometry was used to identify intermediates of the catalytic cycle and delineate differences in substrate reactivity. Our findings provide evidence for the catalytic cycle proceeding through formation of a...
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