The Mechanism of Gold(I)-Catalyzed Hydroalkoxylation of Alkynes: An Extensive Experimental Study
作者:Alexander Zhdanko、Martin E. Maier
DOI:10.1002/chem.201303795
日期:2014.2.10
An extensiveexperimentalstudy of the mechanism of gold(I)‐catalyzed hydroalkoxylation of internal alkynes has been conducted by using NMR spectroscopy. This study was focused on the organogold intermediates, observations of actual catalytic intermediates in situ, and the reaction kinetics that are involved in this reaction. Based on the experimental results, a complete mechanistic picture was established
Dissymmetric gold(i) N-heterocyclic carbene complexes: a key unexpected structural parameter for highly efficient catalysts in the addition of alcohols to internal alkynes
Gold(I) N-heterocycliccarbenecomplexes (Au-NHC) with symmetric (bis-benzyl, -propyl and -mesityl substituents) and dissymmetric (mesityl and alkyl - benzyl or propyl - substituents) NHC ligands were synthesized and tested as catalysts for the addition of methanol to 3-hexyne, as a representative internal alkyne. While symmetric ones – bis-alkyl (propyl or benzyl) or bis-mesityl systems – displayed
合成了具有对称(双苄基,-丙基和-甲基取代基)和不对称(甲基和烷基-苄基或丙基-取代基)NHC金(I)N-杂环卡宾配合物(Au-NHC),并对其进行了催化剂测试的加法甲醇 到 3-己炔,作为代表性的内部炔烃。对称的双烷基(丙基或苄基)或双异丙基体系显示出低活性,而NHC单元上带有一个烷基(苄基或丙基)和一个异戊基的不对称Au-NHC体系出人意料地具有高活性,且速率和周转数高达294 000 h -1和800 000 mol.mol Au -1。
Enzymatic process for the preparation of butyrolactones
申请人:Lonza Ltd
公开号:EP2634180A1
公开(公告)日:2013-09-04
The invention relates to a process for the preparation of a compound of formula
wherein R1 is selected from the group consisting of hydrogen, C2-11-acyl, C4-9-cycloalkanoyl, aryl, aralkyl, aroyl, hetaryl, hetaralkyl and hetaroyl, comprising a biotransformation of a compound of formula
wherein R1 is as defined above, wherein said biotransformation is carried out using a polypeptide having aldo-keto reductase activity or a microorganism containing same.
Hydration and alkoxylation of alkynes catalyzed by NHC–Au–OTf
作者:Mattia Gatto、Walter Baratta、Paola Belanzoni、Leonardo Belpassi、Alessandro Del Zotto、Francesco Tarantelli、Daniele Zuccaccia
DOI:10.1039/c8gc00508g
日期:——
The NHC–Au–OTf [NHC = 1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene] catalyst was tested in the alkoxylation and hydration of alkynes in a wide set of neoteric solvents for the first time. We found that most of these solvents (ethyl lactate, glycerol, propylene carbonate, D-limonene, γ-valerolactone, and p-cymene) are comparable or better solvents with respect to traditional VOSs. An important
and for a long time gold was even thought of as "catalytically dead". This is clearly not the case for cationic phosphanegold(I) complexes (see reaction below), which can catalyze the addition of alcohols to alkynes with turnover frequencies up to 1.5 s-1 and total turnover numbers up to 105 ! R=H, alkyl, Ph, CH2 OH.
金络合物在均相催化中几乎是未知的,并且很长一段时间以来,金甚至被认为是“催化死亡”的。阳离子膦金(I)配合物显然不是这种情况(请参见下面的反应),它可以催化将醇类添加到炔烃中,其周转频率高达1.5 s -1,总周转数高达10 5!R = H,烷基,Ph,CH 2 OH。