Application of the BHQ benzannulation reaction to the synthesis of benzo-fused coumarins
摘要:
A new approach to the synthesis of the 6H-benzo[d]naphthal[,2-b]pyran-6-one ring system present in the gilvocarcin family of antibiotics is described. The key feature of this approach is the application of a new benzannulation strategy (the 'BHQ Reaction') whereby readily available ortho-allylaryl trichloroacetates are transformed into naphthalene derivatives via a cascade of reactions involving an initial ATRC reaction followed by the extrusion of CO2. (C) 2009 Elsevier Ltd. All rights reserved.
Palladium(II) complexes containing mono-, bi- and tridentate carbene ligands. Synthesis, characterisation and application as catalysts in CC coupling reactions
作者:Alison M Magill、David S McGuinness、Kingsley J Cavell、George J.P Britovsek、Vernon C Gibson、Andrew J.P White、David J Williams、Allan H White、Brian W Skelton
DOI:10.1016/s0022-328x(00)00720-8
日期:2001.1
chloride (1f) and the complex [Pd(Me)(tetramethylimidazolin-2-ylidene)2Cl] (2) are reported. Complex 2 shows square planar coordination with the two carbene ligands trans to each other. The carbene ligands are inclined at 65.3° to the coordination plane. Several complexes proved to be highly stable and efficient catalysts for intermolecular Heck and Suzuki couplingreactions, giving turnover numbers
Direct Synthesis of a Copper(II) N-Heterocyclic Carbene Complex in Air
作者:Daniel J. O’Hearn、Robert D. Singer
DOI:10.1021/acs.organomet.7b00489
日期:2017.9.11
reagents or the use of free NHCs. This results in tedious, multistep procedures, making their preparation more time consuming and costly. Herein we report the synthesis and characterization of two air- and moisture-stable Cu(II)-NHC complexes by direct combination of 1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride with copper(II) hexafluorosilicate. Analysis by single-crystal X-ray diffraction revealed
Syntheses, structures and anion exchange properties of accommodative silver chains using a positively charged and flexible ligand
作者:Zongyao Zhang、Yu Yang、Huiyuan Sun、Rui Cao
DOI:10.1016/j.ica.2015.05.021
日期:2015.8
(8). Structural analysis revealed that ligand L has three kinds of conformations in these structures. As benefited by the flexible feature of L, the silver chains in 1–8 are different and are depended on the shape and the size of counter anions. Anion exchange studies showed that crystals of 4, 6 and 8 had anion exchange properties, and the channel size in the corresponding solid state structures played
A hydrido(methyl)(carbene)platinum(IV) complex, using a stabilized Arduengo carbene, has been formed and characterized at low temperature by NMR. The electron-rich carbene complex [PtMe2C3H2N2(CH2-2-py)2}] reacts with MeX (X = I or CF3SO3) to give [PtMe3C3H2N2(CH2-2-py)2}]X and is protonated at low temperature to give [PtHMe2C3H2N2(CH2-2-py)2}]X, X = CF3SO3, BF4, or CF3CO2. At room temperature
已经形成了使用稳定的Arduengo卡宾的氢化(甲基)(卡宾)铂(IV)配合物,并在低温下通过NMR对其进行了表征。富含电子的卡宾络合物[PtMe 2 C 3 H 2 N 2(CH 2 -2-py)2 }]与MeX(X = I或CF 3 SO 3)反应生成[PtMe 3 C 3 H 2 N 2(CH 2 -2-py)2 }] X并在低温下质子化得到[PtHMe 2 C 3 H 2 N 2(CH 2 -2-py)2 }] X,X = CF 3 SO 3,BF 4或CF 3 CO 2。在室温下[PtHMe 2 C 3 H 2 N 2(CH 2 -2-py)2 }] +进行不可逆的甲烷还原还原并二聚,得到双核双甲基(卡宾)铂(II)}络合物阳离子[Pt 2 Me 2 C 3 H 2 N 2(CH 2 -2-py)2 } 2 ] 2+。
Carbene–pyridine chelating 2Fe2S hydrogenase model complexes as highly active catalysts for the electrochemical reduction of protons from weak acid (HOAc)
作者:Lele Duan、Mei Wang、Ping Li、Yong Na、Ning Wang、Licheng Sun
DOI:10.1039/b616645h
日期:——
asymmetrically disubstituted diironcomplexes (micro-pdt)[Fe(CO)(3)][Fe(CO)(eta(2)-L)] (L = 1-methyl-3-(2-pyridyl)imidazol-2-ylidene (NHC(MePy)), 2; 1,3-bis(2-picolyl)imidazol-2-ylidene (NHC(diPic)), 4) and a mono-substituted diironcomplex (mu-pdt)[Fe(CO)(3)][Fe(CO)(2)(NHC(diPic))] (3) were prepared as biomimetic models of the Fe-only hydrogenase active site. X-Ray studies show that the NHC(MePy) and