Iron-Catalyzed, Hydrogen-Mediated Reductive Cyclization of 1,6-Enynes and Diynes: Evidence for Bis(imino)pyridine Ligand Participation
作者:Kevin T. Sylvester、Paul J. Chirik
DOI:10.1021/ja902478p
日期:2009.7.1
The bis(imino)pyridine iron dinitrogen complex (((i)Pr)PDI)Fe(N(2))(2) catalyzes the hydrogen-mediated reductivecyclization of enynes and diynes with turnover frequencies comparable to those of established precious metal catalysts. Amino, oxygenated, and carbon-based substrates are readily cyclized to the corresponding hetero- and carbocycles with 5 mol % iron and 4 atm H(2) at 23 degrees C. Stoichiometric
Nickelocene as an Air- and Moisture-Tolerant Precatalyst in the Regioselective Synthesis of Multisubstituted Pyridines
作者:Il Young Cho、Woo Gyum Kim、Ji Hwan Jeon、Jeong Woo Lee、Jeong Kon Seo、Jongcheol Seo、Sung You Hong
DOI:10.1021/acs.joc.1c00577
日期:2021.7.16
Ni(COD)2-catalyzed cycloaddition reactions to access pyridines have been extensively studied. However, this catalyst typically requires drying procedures and inert-atmosphere techniques for the reactions. Herein, we report operationally simple nickel(0) catalysis to accesssubstituted pyridines from various nitriles and 1,6-diynes without the aid of air-free techniques. The Ni-Xantphos-based catalytic
Highly Enantioselective Construction of a Chiral Spirocyclic Structure by the [2 + 2 + 2] Cycloaddition of Diynes and <i>exo</i>-Methylene Cyclic Compounds
The enantioselective [2 + 2 + 2] cycloaddition of 1,6-diynes with alpha-methylene lactones and cyclic ketones gave various chiral spirocyclic compounds. The reaction proceeded with high enantioselectivity when the rhodium-xylylBINAP complex was used as a chiral catalyst. Not only exo-methylene cyclic compounds but also exo-methylene acyclic compounds could be used as coupling partners for diynes. The
Rhodium-Catalyzed Cyclization of Diynes with Nitrones: A Formal [2+2+5] Approach to Bridged Eight-Membered Heterocycles
作者:Chunxiang Wang、Dongping Wang、Hao Yan、Haolong Wang、Bin Pan、Xiaoyi Xin、Xincheng Li、Fan Wu、Boshun Wan
DOI:10.1002/anie.201407394
日期:2014.10.27
N‐aryl‐substituted nitrones were employed as five‐atom couplingpartners in the rhodium‐catalyzed cyclization with diynes. In this reaction, the nitrone moiety served as a directing group for the catalytic CHactivation of the N‐aryl ring. This formal [2+2+5] approach allows rapid access to bridged eight‐membered heterocycles with broad substrate scope. The results of this study may provide new insight
Iridium(III)-Catalyzed Approach for the Synthesis of Fused Arenes: Access to Isoindolines, Indanes, and Dihydroisobenzofurans
作者:Anne-Laure Auvinet、Mehdi Ez-Zoubir、Savinien Bompard、Maxime R. Vitale、Jack A. Brown、Véronique Michelet、Virginie Ratovelomanana-Vidal
DOI:10.1002/cctc.201300068
日期:2013.8
dihydroisobenzofuran derivatives has been developed through the application of a halogen‐bridged iridium(III) complex to the [2+2+2] cycloaddition of α,ω‐diynes with alkynes. The cycloaddition tolerates a broad range of substitution groups, such as alcohol, alkyl, ether, and halogen, and the chemistry can be extended to prepare the corresponding borylated fused arenes. The reaction shows that hindered