Palladium-Catalyzed, Enantioselective Formal Cycloaddition between Benzyltriflamides and Allenes: Straightforward Access to Enantioenriched Isoquinolines
摘要:
Benzyl and allyltriflamides can engage in Pd-catalyzed oxidative (4+2) annulations with allenes, to produce highly valuable tetrahydroisoquinoline or dihydropyridine skeletons. The reaction is especially efficient when carried out in the presence of designed N-protected amino acids as metal ligands. More importantly, using this type of chiral ligands, it is possible to perform desymmetrizing, annulative C-H activations of prochiral diarylmethylphenyl amides, and thus obtain the corresponding isoquinolines with high enantiomeric ratios.
Highly Efficient Synthesis of Allenes from Trimethylaluminum Reagent and Propargyl Acetates Mediated by a Palladium Catalyst
作者:Qing-Han Li、Jung-Yuan Jeng、Han-Mou Gau
DOI:10.1002/ejoc.201403008
日期:2014.12
A series of propargylacetates were prepared and used as propargyl electrophiles for coupling reactions with trimethylaluminum. The simple catalytic system of palladium(II) acetate (1 mol-%) and tri(o-tolyl)phosphine (2 mol-%) worked efficiently for a wide variety of aromatic and aliphatic propargylacetates, producing the substituted allenes in good to excellent yields of up to 94 % in tetrahydrofuran
制备了一系列乙酸炔丙酯并将其用作炔丙基亲电试剂与三甲基铝进行偶联反应。乙酸钯 (II) (1 mol-%) 和三(邻甲苯基)膦(2 mol-%)的简单催化体系对多种芳香族和脂肪族乙酸炔丙酯有效地工作,产生了良好的取代丙二烯在四氢呋喃中的产率高达 94%。该过程简单易行,为合成取代的丙二烯衍生物提供了一种有效的方法。根据实验结果,提出了一种可能的催化循环。
Assembly of Tetrahydroquinolines and 2-Benzazepines by Pd-Catalyzed Cycloadditions Involving the Activation of C(sp<sup>3</sup>)–H Bonds
作者:Xandro Vidal、José Luis Mascareñas、Moisés Gulías
DOI:10.1021/acs.orglett.1c01594
日期:2021.7.16
Cycloadditionreactions are among the most practical strategies to assemble cyclic products; however, they usually require the presence of reactive functional groups in the reactants. Here, we report a palladium-catalyzed formal (4 + 2) cycloaddition that involves the activation of C(sp3)–H bonds and provides a direct, unconventional entry to tetrahydroquinoline skeletons. The reaction utilizes amidotolyl
Palladium(II)-Catalyzed Annulation between <i>ortho</i>-Alkenylphenols and Allenes. Key Role of the Metal Geometry in Determining the Reaction Outcome
作者:Noelia Casanova、Karina P. Del Rio、Rebeca García-Fandiño、José L. Mascareñas、Moisés Gulías
DOI:10.1021/acscatal.6b00739
日期:2016.5.6
2-Alkenylphenols react with allenes, upon treatment with catalytic amounts of Pd(II) and Cu(II), to give benzoxepine products in high yields and with very good regio- and diastereoselectivities. This contrasts with the results obtained with Rh catalysts, which provided chromene-like products through a pathway involving a β-hydrogen elimination step. Computational studies suggest that the square planar
Tri(<i>o</i>-tolyl)phosphine for highly efficient Suzuki coupling of propargylic carbonates with boronic acids
作者:Junzhe Xiao、Hongwen Luo、Shan Huang、Hui Qian、Shengming Ma
DOI:10.1039/c8cc04186e
日期:——
A highlyefficient catalytic system consisting of Pd2(dba)3·CHCl3 and tri(o-tolyl)phosphine has been identified for the coupling of propargylic carbonates with different types of organo boronic acids at room temperature. Excellent central-to-axial chirality transfer was also demonstrated.
Synthesis of β,
<scp>γ‐unsaturated</scp>
ketones with quaternary centers through regioselective hydroacylation of allenes with acyl chlorides
作者:Subin Yoon、Kyeongmin Lee、Telma Kamranifard、Yunmi Lee
DOI:10.1002/bkcs.12629
日期:2022.12
The one-pot synthesis of β,γ-unsaturatedketones bearing all-carbon quaternary centers at the α-position via a highly regioselective hydroacylation of allenes using acyl chlorides and aluminum hydride is reported. The Cu-catalyzed hydroalumination of 1,1-disubstituted and 1,1,3-trisubstituted allenes with diisobutylaluminum hydride resulted in allylaluminum reagents that underwent regioselective acylation