Annulation of furan-bridged 10-membered rings on N-heterocycles through [8+2] cycloaddition of dienylazaisobenzofurans and dimethyl acetylenedicarboxylate
作者:Priyabrata Roy、Binay K. Ghorai
DOI:10.1016/j.tetlet.2011.08.094
日期:2011.10
One-pot three-componentcoupling of o-alkynylheteroaryl carbonyl derivatives with α,β-unsaturated Fischer carbene complexes and dimethyl acetylenedicarboxylate leading to the synthesis of heterocyclic analogues of furanophane derivatives has been explored. This involves the generation of conformationally flexible dienylazaisobenzofuran intermediate as transient intermediates, which undergo [8+2] cycloaddition
6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) capped Pd(0) nanoparticles (TzPdNPs) as a catalyst in the Sonogashiracoupling of aryl halides in aqueous medium with diminished homocoupling is reported. The methodology provides a facile route to obtain polyfunctional alkynes under ligand- and copper-free conditions. The procedure is also efficient for aryl chlorides.
Tandem furo[3,4-b]pyridine formation—Diels–Alder reaction: an approach to the synthesis of nitrogen containing heterocyclic analogues of 1-arylnaphthalene lignans
作者:Gouranga P. Jana、Binay K. Ghorai
DOI:10.1016/j.tet.2007.09.007
日期:2007.11
derivatives has been examined. The reaction affords furo[3,4-b]pyridine as transient intermediates; the latter undergo [4+2] cycloaddition with an electron-deficient dienophile. Acid/base-induced ring opening of the exo-cycloadducts followed by aromatization give substituted quinolines related to heterocyclicanalogues of 1-arylnaphthalenelignans. An intramolecular variant of this protocol is also
已经研究了费歇尔卡宾配合物与2-炔基-3-吡啶羰基衍生物的偶联。反应得到呋喃并[3,4- b ]吡啶作为过渡中间体。后者与缺电子的亲双烯体进行[4 + 2]环加成反应。酸/所述的碱诱导的环开口外-cycloadducts随后芳构给予取代的喹啉与1- arylnaphthalene木脂杂环类似物。该方案的分子内变体也可通过使用未活化的烯基系链来实现。然而,桥接的环加合物在经历自发开环以产生醇时是可溶的。该方法对于呋喃[3,4- b]喹啉中间体首次出现,可被双亲亲虫捕获。