Accessing a Biologically Relevant Benzofuran Skeleton by a One-Pot Tandem Heck Alkynylation/Cyclization Reaction Using Well-Defined Palladium N-Heterocyclic Carbene Complexes
作者:Anuj Kumar、Manoj Kumar Gangwar、A. P. Prakasham、Darshan Mhatre、Alok Ch. Kalita、Prasenjit Ghosh
DOI:10.1021/acs.inorgchem.5b02727
日期:2016.3.21
successfully catalyzed the one-pot tandem Heck alkynylation/cyclization reaction of 2-iodophenol with a variety of terminal alkyne substrates, yielding 2-substituted benzofuran derivatives. The mononuclear complexes 3b and 3c were nearly half as active as the representative dinuclear analogue 1c under analogous reaction conditions, thereby implying that, at the same mole percent of the palladium loading
定义明确的钯N-杂环卡宾(NHC)络合物用于一锅串联Heck炔基化/环化序列中,在无铜条件下以省时高效的步骤减少的方式制备生物学上相关的苯并呋喃化合物。特别是,烷基桥接的NHC配体的一系列双核钯配合物1b – 1e和2b – 2e,即1,1'-di-R 1 -4,4'-R 2 -di-1 ,2,4-triazoline-5,5'-diylid-2-ene](R 1 = i -Pr; R 2 =-(CH 2)2 –,-(CH 2)3−)及其单核类似物反式-(NHC)PdBr 2(吡啶)(3b)和顺式-(NHC)PdBr 2(PPh 3)(3c),成功催化了一锅串联的Heck烷基化/环化反应具有各种末端炔烃底物的2-碘苯酚,生成2-取代的苯并呋喃衍生物。在类似的反应条件下,单核络合物3b和3c的活性几乎是典型的双核类似物1c的一半,因此暗示在钯载量相同的摩尔百分比下,单金属3b和3c双金属1