Efficient Copper-Catalyzed Cross-Coupling Reaction of Alkynes with Aryl Iodides
作者:Che-Hung Lin、Yu-Jen Wang、Chin-Fa Lee
DOI:10.1002/ejoc.201000653
日期:——
A copper-catalyzed cross-coupling reaction of alkynes with aryl iodides is described. The system tolerates a broad range of functional groups and enables the use of sterically demanding substrates with only 1.0-2.5 mol-% of Cu 2 O and 1.0-2.5 mol-% of xantphos as the catalyst.
描述了炔烃与芳基碘化物的铜催化交叉偶联反应。该系统可耐受广泛的官能团,并能够使用空间要求严格的底物,只需 1.0-2.5 mol-% 的 Cu 2 O 和 1.0-2.5 mol-% 的黄磷作为催化剂。
Regioselective synthesis of phthalans via Cu(OTf)2-catalyzed 5-exo-dig intramolecular hydroalkoxylation of 2-(ethynyl)benzyl alcohols
efficient, regioselective Cu(OTf)2-catalyzed 5-exo-dig intramolecular hydroalkoxylation of 2-(ethynyl)benzyl alcohol, which provides a concise access to functionalized phthalan in high yields has been developed. A wide range of substrates possessing terminal, internal, and heteroaromatic alkynes can be efficiently transformed into the targeted phthalans. Substrates with primary, secondary, and tertiary benzyl
Alkaline Earth Catalysis of Alkynyl Alcohol Hydroalkoxylation/Cyclization
作者:Christine Brinkmann、Anthony G. M. Barrett、Michael S. Hill、Panayiotis A. Procopiou、Stephanie Reid
DOI:10.1021/om3008663
日期:2012.10.22
Heavier alkaline earth bis(trimethylsilyl)amides [AeN(SiMe3)(2)}(2)](2) (Ae = Ca, Sr, Ba) are shown to act as effective precatalysts for the regioselective intramolecular hydroalkoxylation/cyclization of a wide range of alkynyl and allenyl alcohols. In the majority of cases, cyclization of alkynyl alcohols produces mixtures of the possible endo- and exocyclic enol ether products, rationalized as a consequence of alkynylalkoxide isomerization to the corresponding allene derivatives. Cyclization rates for terminal alkynyl alcohols were found to be significantly higher than for substrates bearing internal alkynyl substituents, while the efficacy of cyclization was in general found to be determined by a combination of stereoelectronic influences and the thermochemical viability of the specific alkaline earth metal catalysis, which we suggest is determined by the individual M-O bond strengths. Kinetic studies have provided a rate law pertaining to a pronounced catalyst inhibition with increasing [substrate], indicating that turnover-limiting insertion of C-C unsaturation into the M-O bond requires the dissociation of substrate molecules away from the Lewis acidic alkaline earth center.
Palladium-Catalyzed Copper-Free Sonogashira Coupling of 2-Bromoarylcarbonyls: Synthesis of Isobenzofurans via One-Pot Reductive Cyclization
作者:Alavala Krishna Reddy、Gedu Satyanarayana
DOI:10.1055/s-0036-1588513
日期:2017.12
Abstract Palladium-catalyzed copper-free Sonogashira coupling of 2-bromocarbonyls is presented. This method afforded the 2-alkynylaryl carbonyls, useful synthons for the accomplishment of many carbocyclic and heterocyclic motifs. Significantly, the strategy was extended to the one-pot synthesis of isobenzofurans via reduction followed by intramolecular 5-exo-dig cyclization. Palladium-catalyzed copper-free
A Tandem Reaction of Benzyne with Functionalized Benzylidenephthalan To Afford Phenanthro[10,1-<i>bc</i>]furan
作者:Hai Xiao Siyang、Xu Rui Wu、Hui Ling Liu、Xin Yan Wu、Pei Nian Liu
DOI:10.1021/jo402701q
日期:2014.2.7
A tandem reaction of benzyne with functionalized benzylidenephthalan for the synthesis of a variety of phenanthro[10,1-bc]furans has been achieved for the first time in moderate to good yields. The reaction mechanism involves a Diels–Alder reaction and an intermolecular nucleophilic addition reaction as the key steps.
首次以中等至良好的产率实现了苯并炔与功能化的亚苄基萘的串联反应,以合成多种菲[10,1- bc ]呋喃。反应机理包括Diels-Alder反应和分子间亲核加成反应为关键步骤。