Tandem Ullmann–Goldberg Cross-Coupling/Cyclopalladation-Reductive Elimination Reactions and Related Sequences Leading to Polyfunctionalized Benzofurans, Indoles, and Phthalanes
作者:Faiyaz Khan、Mehvish Fatima、Moheb Shirzaei、Yen Vo、Madushani Amarasiri、Martin G. Banwell、Chenxi Ma、Jas S. Ward、Michael G. Gardiner
DOI:10.1021/acs.orglett.9b02235
日期:2019.8.16
Cu[I]- and Pd[0]-based catalysts, compounds such as 1 and 7 engage in tandem Ullmann–Goldberg cross-coupling and cyclopalladation-reductive elimination reactions to givebenzofurans such as 8. Related reactions involving hetero-Michael additions of o-halogenated phenols or anilines to propiolates and the Pd[0]-catalyzed cyclization of the resulting conjugates provide, in a one-pot process, alternately
3-Disubstituted benzofurans were synthesized from acrolein dimer and 1,3-dicarbonyl compounds by using N-bromosuccinimide as an oxidizing agent. The method was used to synthesize two commercial drug molecules, benzbromarone and amiodarone. The proposed mechanism of the reaction involves a N-bromosuccinimide (NBS)-assisted autotandem catalysis with Lewis acid catalyst. To proof the proposed mechanism
Cu-Catalyzed Reaction of 1,2-Dihalobenzenes with 1,3-Cyclohexanediones for the Synthesis of 3,4-Dihydrodibenzo[<i>b,d</i>]furan-1(2<i>H</i>)-ones
作者:Nayyef Aljaar、Chandi C. Malakar、Jürgen Conrad、Sabine Strobel、Thomas Schleid、Uwe Beifuss
DOI:10.1021/jo3014275
日期:2012.9.21
The Cu(I)-catalyzed reaction of 1-bromo-2-iodobenzenes and other 1,2-dihalobenzenes with 1,3-cyclohexanediones in DMF at 130 °C using Cs2CO3 as a base and pivalic acid as an additive selectively delivers 3,4-dihydrodibenzo[b,d]furan-1(2H)-ones with yields ranging from 47 to 83%. The highly regioselective domino process is based on an intermolecular Ullmann-type C-arylation followed by an intramolecular
在130°C下,以Cs 2 CO 3为碱,新戊酸为添加剂,在DMF中Cu(I)催化1-溴-2-碘苯和其他1,2-二卤代苯与1,3-环己二酮的反应提供3,4-dihydrodibenzo [ b,d ]呋喃-1(2 H)-one,产率为47%至83%。高度区域选择性的多米诺过程是基于分子间的Ullmann型C-芳基化,然后是分子内的Ullmann型O-芳基化。通过使用取代的1-溴-2-碘苯和取代的1,3-环己二酮作为底物,可以得到取代的产物。与无环1,3-二酮反应生成相应的苯并[ b]呋喃。
Divergent synthesis of 3,4-dihydrodibenzo[<i>b</i>,<i>d</i>]furan-1(2<i>H</i>)-ones and isocoumarins <i>via</i> additive-controlled chemoselective C–C or C–N bond cleavage
Rh(III)-Catalyzed C–C/C–Obondformationbetween cyclic 2-diazo-1,3-diketones and salicylamides with additive-controlled chemoselectivity is described. The reaction proceeded under mild reaction conditions and exhibited good functional group tolerance and scalability. 3,4-Dihydrodibenzo[b,d]furan-1(2H)-ones were obtained in moderate to excellent yields (55–90%) through a tandem N–H activation/C–C cleavage/etherification
Gold(III)-Catalyzed Tandem Reaction of<i>O</i>-Arylhydroxylamines with 1,3-Dicarbonyl Compounds: Highly Selective Synthesis of 3-Carbonylated Benzofuran Derivatives
A highly regioselective protocol for the synthesis of 3-carbonylated benzofuran derivatives has been developed involving the gold(III)-catalyzed tandem condensation/rearrangement/cyclization reaction of O-arylhydroxylamines with 1,3-dicarbonyl compounds.