Electrophilic Cyclization of (Z)-Selenoenynes: Synthesis and Reactivity of 3-Iodoselenophenes
摘要:
We present here our results of the electrophilic cyclization reaction of (Z)-selenoenynes with different electrophiles such as I-2, ICl, PhSeBr, and PhSeCl. The cyclization reaction proceeded cleanly under mild reaction conditions, and 3-substituted selenophenes were formed in moderate to excellent yields. We observed that the nature of solvent and structure of (Z)-selenoenyne were important to the cyclization reaction. In addition, the obtained 3-iodoselenophenes were readily transformed to more complex products using a metal-halogen exchange reaction with n-BuLi and trapping the intermediate formed with aldehydes, furnishing the desired secondary alcohols in good yields. Conversely, using the palladium or copper catalyzed cross-coupling reactions with terminal alkynes or alkyl alcohols, we were able to convert 3-iodoselenophene to Sonogashira or Ullmann type products, respectively, in good yields.
Synthesis and Properties of New Dimeric η<sup>2</sup>-Diyne Complexes of Cobalt Linked through an Azobenzene Ligand
作者:Consuelo Moreno、Avelina Arnanz、Rosa-María Medina、María-José Macazaga、Mario Pascual、Eva M. García-Frutos、Esther Martínez-Gimeno、María-Luisa Marcos
DOI:10.1021/acs.organomet.5b00257
日期:2015.6.22
analogous reactions from 0 and the alkynyl-cobalt complexes Co2(CO)4(μ-L-L)(μ2-η2-SiMe3C2)](C≡CH) (L-L = dppm, dmpm) afforded 12–14. Complexes 4–7 and 15 have been obtained by direct reactionbetween Co2(CO)8 and the organic ligands 1–3. In order to increase the stabilization of Co–Co bonds, diphenylphosphinomethane-substituted alkyne-carbonyl complexes 8–11 were prepared by substitution reaction of carbonyl
A novel pathway for homocoupling of terminal alkynes has been described using cyclopalladatedferrocenylimine 1 or 2/CuI as catalyst in the air. This catalytic system could tolerate several functional groups. The palladacycle 2 in the presence of n-Bu4NBr as an additive could be applied to Sonogashira cross-coupling reaction of aryl iodides, aryl bromides, and some activated aryl chlorides with terminal
Gold-Catalyzed Oxidative Coupling of Alkynes toward the Synthesis of Cyclic Conjugated Diynes
作者:Xiaohan Ye、Haihui Peng、Chiyu Wei、Teng Yuan、Lukasz Wojtas、Xiaodong Shi
DOI:10.1016/j.chempr.2018.07.004
日期:2018.8
developed as an efficient approach for the synthesis of challenging cyclic conjugated diynes (CCD). Compared with the classic copper-promoted oxidative coupling reaction of alkynes, this gold-catalyzed process exhibited a faster reaction rate due to rapid reductive elimination from the Au(III) intermediate. This unique reactivity thus allowed a challenging diyne macrocyclization to take place with high
Synthesis and structural characterization of a monomeric di-copper-substituted silicotungstate [γ-H2SiW10O36Cu2(μ-1,1-N3)2]4− and the catalysis of oxidative homocoupling of alkynes
acetonitrile, benzonitrile, and 1,2-dichloroethane, showed that complex 1 was present as a monomer of the di-copper-substituted γ-Keggin silicotungstate. Complex 1 could act as an effective homogeneous catalyst for the oxidativehomocoupling of various types of alkynes, including aromatic, aliphatic, and heteroatom-containing ones. The reaction possibly proceeds as follows: First, the ligand exchange
具有双-μ - 1,1-叠氮基配体的双铜取代的γ - Keggin硅钨酸盐TBA 4 [ γ- H 2 SiW 10 O 36 Cu 2(μ -1,1-N 3)2 ](1,TBA在水性介质中合成=(四TBA =四-正丁基铵)。1的阴离子部分的晶体结构是基-基末端叠氮桥联双铜取代的γ - Keggin硅钨酸盐的单体。的NMR和CSI-MS谱1在乙腈,苄腈和1,2-二氯乙烷等有机溶剂中的分析表明,配合物1作为双铜取代的γ - Keggin硅钨酸盐的单体存在。配合物1可以作为有效的均相催化剂,用于各种类型的炔烃(包括芳族,脂族和含杂原子的炔烃)的氧化均偶联。反应可能如下进行:首先,配体交换在1中的叠氮基之间进行。 和炔基通过二铜(II)-炔基中间体与还原的铜(I)物种形成相应的二炔,然后还原的物种被分子氧再氧化,氧化的物种与炔反应生成炔基中间的。
Scope and reaction mechanism of an aerobic oxidative alkyne homocoupling catalyzed by a di-copper-substituted silicotungstate
TBA = tetra-n-butylammonium) could act as an efficient reusable homogeneous catalyst for the aerobic oxidative alkyne homocoupling. Various kinds of structurally diverse terminalalkynes including aromatic, heteroaromatic, aliphatic, double bond-containing, silylacetylene, propargylicalcohol, and propargylic amine derivatives could selectively be converted into the corresponding diynes in the presence of I.