Head-to-tail homo- and heterodimerization of vinylamides by hidden proton catalysis
摘要:
Chemoselective dimerization of vinylamides is reported. A number of vinylacylamides were shown to undergo stereoselective cationic intermolecular head-to-tail homodimerization. Correspondingly, chemoselective heterodimerization reactions readily afforded hydroalkenylation of vinylacylamide with vinylsulfonamide. Different mild methods for hidden proton catalysis were studied. The in situ generation of, e.g., HSbF6 from the [Au]SbF6-PhC equivalent to CHI catalytic systems was applied. Successful vinylacylamide head-to-tail dimerizations seem to be dependant on the ability of N-C-O acylamide electron delocalization, affording stabilized intermediates. In general, the reactions demonstrate the ability of vinylacylamides to effectively undergo hydroalkenylation to afford 1,3-N,N-functionalized (E)-but-1-ene products. (C) 2013 Elsevier Ltd. All rights reserved.
Head-to-tail homo- and heterodimerization of vinylamides by hidden proton catalysis
作者:Naseem Iqbal、Guro Blakstad、Anne Fiksdahl
DOI:10.1016/j.tet.2013.12.041
日期:2014.2
Chemoselective dimerization of vinylamides is reported. A number of vinylacylamides were shown to undergo stereoselective cationic intermolecular head-to-tail homodimerization. Correspondingly, chemoselective heterodimerization reactions readily afforded hydroalkenylation of vinylacylamide with vinylsulfonamide. Different mild methods for hidden proton catalysis were studied. The in situ generation of, e.g., HSbF6 from the [Au]SbF6-PhC equivalent to CHI catalytic systems was applied. Successful vinylacylamide head-to-tail dimerizations seem to be dependant on the ability of N-C-O acylamide electron delocalization, affording stabilized intermediates. In general, the reactions demonstrate the ability of vinylacylamides to effectively undergo hydroalkenylation to afford 1,3-N,N-functionalized (E)-but-1-ene products. (C) 2013 Elsevier Ltd. All rights reserved.