进行了钯催化的分子内串联环化反应,以合成致密的顺式/顺式稠合的氮杂四环结构。该过程涉及钯(II)催化的好氧aza-Wacker反应,然后是钯(0)催化的Heck反应。系统地研究了溶剂和苯的取代方式对一锅两步级联反应的影响,并提出了可能的机理。使用钯催化的aza-Wacker-Heck环化反应,也可以快速合成应变的五氢苯并[ f ]环戊基[ hi ]吲哚并嗪-6-和外消旋的γ-二十烷。
Palladium-Catalyzed Aerobic Oxidative Cyclization of Aliphatic Alkenyl Amides for the Construction of Pyrrolizidine and Indolizidine Derivatives
作者:Dan Yang、Kai-Yip Lo、Liu Ye
DOI:10.1055/s-0036-1588502
日期:2017.8
An efficient palladium-catalyzed aerobic oxidative cyclization has been developed to synthesize a variety of pyrrolizidine and indolizidine derivatives from simple aliphatic alkenyl amides in moderate to good yields. The reaction features the capability of accessing various N-heterocycles and the use of molecular oxygen (1 atm) as the green oxidant.
Palladium-Catalyzed Regioselective C–H Iodination of Unactivated Alkenes
作者:Benedikt S. Schreib、Erick M. Carreira
DOI:10.1021/jacs.9b03998
日期:2019.6.5
A palladium-catalyzedC-H iodination of unactivated alkenes is reported. A picolinamide directing group enables the regioselective functionalization of a wide array of olefins to furnish iodination products as single stereoisomers. Mechanistic investigations suggest the reversible formation of a six-membered alkenyl palladacycle intermediate through a turnover-limiting C-H activation.
OER for enhancing HER. The increased H2 production can be obtained at cathode; meanwhile, a variety of aromatic and aliphatic primary amines are selectively electrooxidized to nitriles with good yields at the anode. Mechanistic investigations suggest that NiII/NiIII may serve as the redox active species for the primary amines transformation. Hydrophobic nitrile products can readily escape from aqueous
对于电催化水分解,缓慢的阳极氧气逸出反应(OER)限制了阴极氢气逸出反应(HER)。因此,开发具有加速动力学的替代性阳极反应以生产特别是与HER结合的增值化学品非常重要。现在,据报道,NiSe纳米棒阵列在水中催化的热力学上更有利的伯胺(-CH 2 -NH 2)电氧化代替了OER以增强HER。可以在阴极获得增加的H 2生成量。同时,各种芳香族和脂肪族伯胺在阳极被选择性地电氧化成腈,并具有良好的收率。机理研究表明,Ni II / Ni III可以用作伯胺转化的氧化还原活性物质。疏水性腈产品可以很容易地从水电解质/电极界面逸出,避免了催化剂的失活,从而促进了连续的克级合成。
Palladium-Catalyzed Transformation of Cyclobutanone <i>O</i>-Benzoyloximes to Nitriles via C−C Bond Cleavage
by the kind of ligand employed. The sequential reaction composed of the C−C bond cleavage and the subsequent intra- and intermolecular C−C bondformationsvia the corresponding alkylpalladium species is also demonstrated. For example, an oxime having an alkynyl moiety at a suitable position reacts with a variety of alkenes to afford nitriles bearing dienylcyclopentane moiety in moderate to good yields
Metal-Free Oxidative Cyclization of Urea-Tethered Alkenes with Hypervalent Iodine
作者:Brian M. Cochran、Forrest E. Michael
DOI:10.1021/ol8022165
日期:2008.11.6
A metal-free oxidative cyclization of ureas onto unactivated alkenes using iodosylbenzene and an acid promoter is described. The products isolated are predominantly bicyclic isoureas resulting from an intramolecular oxyamination reaction. The acid type and urea substitution have a strong effect on the product formed. A variety of substrates form the isourea with high diastereoselectivity via syn addition