Pd-Catalyzed Asymmetric 5-exo-trig Cyclization/Cyclopropanation/Carbonylation of 1,6-Enynes for the Construction of Chiral 3-Azabicyclo[3.1.0]hexanes

We herein disclose a mild and efficient access to chiral 3-azabicyclo[3.1.0]hexanes via a Pd-catalyzed asymmetric 5-exo-trig cyclization/cyclopropanation/carbonylation of 1,6-enynes. Various nucleophiles, such as alcohols, phenols, amines and water, are well compatible with the reaction system. This reaction forms three C−C bonds, two rings, two adjacent quaternary carbon stereocenters as well as one C−O/C−N bond with excellent regio- and enantioselectivities. The products could be further functionalized to generate a library of 3-azabicyclo[3.1.0]hexane frameworks.     

二氧化碳和胺催化合成甲酰胺反应研究

二氧化碳是碳资源利用的最终形式,也是一种绿色的碳一资源。通过催化化学的方法将二氧化碳转化为高附加值精细化学品是二氧化碳循环利用的有效途径。酰胺类化合物是一类重要的化工原料和溶剂,广泛应用于医药、农药、日用化学品及石油化工等众多领域且需求量巨大。因此,以二氧化碳为羰源,通过高效催化体系的建立实现二氧化碳与胺反应合成甲酰胺具有重要意义。本文分别从催化体系、还原剂和反应机理等角度综述了这一领域近年来的主要研究成果。其中,催化体系可分为贵金属催化剂如Ir、Pd、Pt、Ru、Rh,非贵金属催化剂如Ni、Mo、Cu、Fe、Co、Zn、Al,有机分子催化剂和无催化剂体系,常用的还原剂为H₂,硅烷和硼烷。在此基础上,对不同催化体系的典型反应机理进行了讨论。     

Indium-catalyzed reaction for the synthesis of carbamates and carbonates: selective protection of amino groups

We developed a simple, efficient, and selective method for preparing organic carbamates and carbonates using a catalytic amount of indium. A wide range of carbamates and carbonates were synthesized in high yields. The method is also applicable to the selective protection of amino groups under mild conditions.     

Co2(CO)8-induced domino reactions of ethyl diazoacetate, carbon monoxide and ferrocenylimines leading to 2-(1-ferrocenyl-methylidene)-malonic acid derivatives

Novel 2-(1-ferrocenyl-methylidene)-malonic acid derivatives are obtained upon reacting ethyl diazoacetate, carbon monoxide and ferrocenylimines in the presence of Co₂(CO)₈ as catalyst under mild conditions. Presumably, the reaction involves three steps taking place in a domino fashion, (i) carbonylation of ethyl diazoacetate leading to a ketene derivative, (ii) [2+2] cycloaddition of the ketene with the ferrocenylimine present in the reaction mixture resulting in the formation of a β-lactam and (iii) N(1)-C(4) cleavage of the β-lactam ring. In most cases, 2-(1-ferrocenyl-methylidene)-malonic acid derivatives are obtained as a separable mixture of E- and Z-isomers in ratios depending on the structure of the imine component.     

One-pot synthesis of 4(3H)-quinazolinones from azides, alkynes, anilines, and carbon monoxide

A one-pot synthesis of 4(3H)-quinazolinones from terminal alkynes, sulphonyl azide, o-iodoanilines, and carbon monoxide has been developed. This cascade process includes the copper-catalyzed three-component reaction of alkyne, azide and amine, the palladium-catalyzed carbonylation, and the Lewis acid catalyzed hydrolysis of sulfonamide.     

过渡金属催化的烯烃羰基化反应现状与进展

阐述了烯烃羰基化反应在区域选择性和立体选择性方面的现状与最新进展,同时对羰基化反应新进展－超临界二氧化碳流体作为反应介质也作了综述。     

Reductive carbonylation of nitrobenzene over Pd/Fe/I2/Py and Pd/C/Fe/I2/Py catalytic systems

A simple catalytic system containing metallic palladium, iron and iodine has been shown to be very active in the carbonylation of nitrobenzene to carbamate. The influence of the components of the catalytic system studied on its selectivity and activity has been established. It has been found that the catalytic activity of palladium supported on carbon (using both lignite coal and bituminous coal) was not lower than the activity of metallic palladium. This revised version was published online in August 2006 with corrections to the Cover Date.     

Studies of reactions of o-xylylene-α,α′-dihalides with palladium complexes and the catalytic synthesis of 3-isochromanone

Homogeneous catalysis by palladium complexes with phosphorus(III) ligands of the carbonylation of o-xylylene dihalides in the presence of water to form 3-isochromanone has been studied. Triphenylphosphine was found to provide the most effective catalyst, and by-products and intermediates of systems containing this ligand have been investigated. 2-Indanone is one by-product but is unstable to decomposition under catalytic conditions. Excess PPh₃ is necessary to prolong activity of the catalyst but is also transformed to bis-phosphonium compound [o-C₆H₄(CH₂PPh₃)₂]X₂ (X = Cl or Br); this quaternization has been investigated and the structure of the bromide salt determined by X-ray diffraction. An unstable oxidative addition product of Pd(PPh₃)₄ was detected as a probable intermediate and related to the previously reported but catalytically-inactive complex trans-Pd(o-CH₂C₆H₄CH₂Cl)Cl(PMe₃)₂, which has been structurally characterized by X-ray diffraction in this work.     

两种催化裂化干气加工利用方案的对比

催化裂化干气直接加工利用是炼厂副产气体综合利用的重要内容。本文选择工艺技术比较成熟的两种加工方案进行技术经济对比,结论是烃化制乙苯方案的经济性能比羰基化制丙醛、丙酸方案差,但从工艺开发成熟程度和市场需求来看,前一方案的发展规模将比后一方案大。     

Synthesis of aromatic acids via catalysed methyl formate-chloroarene reactions

Chlorobenzene and more generally, chloroarenes, can be converted into aromatic acids via catalytic reaction with aqueous methyl formate under biphasic conditions. The only efficient catalyst is [PdCl₂(PCy₃)₂] (Cy = cyclohexyl). [RU₃(CO)₁₂] and ammonium formate improve yield and selectivity. The mechanism should involve oxidative addition of the C---Cl bond to a zero-valent Pd species followed by CO insertion. The palladium catalyst may also directly activate methyl formate. The procedure is convenient (no solvent, no initial pressurization) and at least as efficient as previously described methods.