Triynes having a phenylene‐bridged 1,5‐diyne moiety were transformed into substituted tetraphenylenes by the title sequence. A cationic Rh–ligand species catalyzed this highly enantioselective reaction. This protocol is a new and easy approach to the construction of the tetraphenylene skeleton and enables an efficient asymmetric synthesis (see scheme; R=H; Z=NTs, C(CO2Me)2, O).
具有亚苯基桥接的1,5-二炔部分的三炔通过标题序列转化为取代的四亚苯基。阳离子Rh-配体物种催化了这种高度对映选择性的反应。该协议是一种构造四亚苯基骨架的新方法,可轻松实现高效的不对称合成(请参见方案; R = H; Z = NTs,C(CO 2 Me)2,O)。
Catalytic Generation of Arynes and Trapping by Nucleophilic Addition and Iodination
A fair exchange: In the title reaction, alkynyllithium serves as an initiator for benzyne generation through an iodine–lithium exchange (see scheme; Tf=trifluoromethanesulfonyl). When performed in the presence of stoichiometric amounts of a nucleophile, the generated benzyne undergoes attack by lithio nucleophiles to generate aryllithium, which is then iodinated by iodoalkyne to give the iodoarenes
Site-specific preparation of 4-substituted-6-fluoro(carboalkoxyl)benzo[b]furans and benzo[b]thiophenes via base-catalyzed cyclization of enyne derivatives
作者:Yi Wang、Donald J. Burton
DOI:10.1016/j.jfluchem.2007.05.019
日期:2007.9
synthesis of 4-substituted-6-fluoro(carboalkoxyl)benzo[b]furans and benzo[b]thiophenes is described. The reactions of heterocyclic aromatic aldehydes with a Wittig reagent, followed by Sonogashira reaction with terminal alkynes, and subsequent base-catalyzedcyclization site-specifically provide 4-substituted-6-fluoro(carboalkoxyl)benzo[b]furans and benzo[b]thiophenes in good yields.
描述了4-取代的6-氟(羰基烷氧基)苯并[ b ]呋喃和苯并[ b ]噻吩的位点特异性合成。杂环芳族醛与Wittig试剂反应,然后与末端炔烃进行Sonogashira反应,然后进行碱催化的环化位点,可特异性地提供4-取代的6-氟(羰基烷氧基)苯并[ b ]呋喃和苯并[ b ]噻吩丰产。
<i>Trans-</i> and <i>Cis-</i>Selective Lewis Acid Catalyzed Hydrogermylation of Alkynes
作者:Todd Schwier、Vladimir Gevorgyan
DOI:10.1021/ol0521026
日期:2005.11.1
[reactions: see text] The first examples of Lewis acid catalyzed hydrogermylation of alkynes have been demonstrated. It was found that this method has much higher functional group compatibility compared to the known Lewis acid catalyzed hydrosilylation and hydrostannation reactions. Remarkably, the stereochemical outcome of this hydrogermylation reaction depends on the nature of the alkyne used: proceeding
Copper(I)-Catalyzed Formation of Isoquinoline and Quinoline Substituted Isobenzofurans
作者:Chittala Emmaniel Raju、Sridhar Balasubramanian、Galla V. Karunakar
DOI:10.1021/acs.orglett.2c00864
日期:2022.4.22
An efficient synthetic organic transformation was developed to access isoquinoline-substituted isobenzofurans by reaction of substituted 1,5-diynes with isoquinoline N-oxides. Moderate to excellent yields of isoquinoline-derived isobenzofurans were achieved by formation of a new C–C and two C–O bonds in the presence of coppercatalyst in onepot. whereas quinoline-substituted isobenzofurans were obtained