Formation of benzofurans in a stoichiometric annulation reaction between stable Pallada (II) Cycles hypervalent vinyl- and alkynyl(phenyl)iodonium salts
作者:Piyali Datta Chaudhuri、Ruiyun Guo、Helena C. Malinakova
DOI:10.1016/j.jorganchem.2007.11.034
日期:2008.2
Stable pallada(II)cycles featuring Csp2–Pd and Csp3–Pd bonds reacted with vinyl- and alkynyl(phenyl)iodonium salts to generate two new geminal carbon–carbon bonds to the terminal carbon of the vinyl and alkynyl substituents providing benzofuran and dihydrobenzofuran heterocycles. The new annulation process was rationalized by the involvement of Pd(IV) intermediates arising via an initial oxidative
An Allylpalladium(IV) Intermediate in the Synthesis of Highly Substituted Benzoxepines and Benzopyrans via Reactions of Stable Pallada(II)cycles with Allyl Bromides
作者:Ruiyun Guo、Janelle L. Portscheller、Victor W. Day、Helena C. Malinakova
DOI:10.1021/om7002865
日期:2007.7.1
Stable pallada(II)cycles L2Pd-1-C6H5-2-OCHCO2Et, featuring a Pd-bonded sp3-hybridized stereogenic carbon and bipyridine or bis(imine) auxiliary ligands (L-L), reacted with allyl bromides via a Pd(II)−Pd(IV)-mediated process involving a direct C(sp2)−H functionalization to afford highly substituted benzoxepines or benzopyrans. An allylpalladium(IV) complex, which was detected by low-temperature 1H NMR
稳定的pallada(II)环L 2 Pd-1-C 6 H 5 -2-OCHCO 2 Et,具有Pd键结合的sp 3-杂化立体碳和联吡啶或双(亚胺)辅助配体(LL),与烯丙基反应溴化物通过Pd(II)-Pd(IV)介导的过程,涉及直接C(sp 2)-H官能化,以提供高度取代的苯并二氢吡啶或苯并吡喃。通过低温1 H NMR分析检测到并通过X射线晶体学表征的烯丙基钯(IV)配合物在反应序列中表现为中间体。