Palladium-Catalyzed Oxidative Arylating Carbocyclization of Allenynes
作者:Youqian Deng、Teresa Bartholomeyzik、Andreas K. Å. Persson、Junliang Sun、Jan-E. Bäckvall
DOI:10.1002/anie.201107592
日期:2012.3.12
Vinylallenes or cross‐conjugated trienes are obtained selectively in the title reaction (see scheme). Two possible mechanisms are suggested to rationalize the formation of the different types of products. Control experiments indicate that p‐benzoquinone (BQ) plays an important role as a ligand in addition to its role as an oxidant. E=CO2Me.
在标题反应中有选择地获得乙烯基丙烯烯或交叉共轭三烯(参见方案)。建议了两种可能的机制来合理化不同类型产品的形成。对照实验表明,对苯醌(BQ)除起氧化剂作用外,还起着重要的配体作用。E = CO 2我。
Control of Selectivity in Palladium-Catalyzed Oxidative Carbocyclization/Borylation of Allenynes
In control: A highly selective carbocyclization/borylation of allenynes with bis(pinacolato)diboron (B2pin2) under palladium catalysis and with p‐benzoquinone (BQ) as the oxidant was developed. The use of either LiOAc⋅2 H2O with 1,2‐dichloroethane (DCE) as the solvent or BF3⋅Et2O together with THF is crucial for the selective formation of borylated trienes and vinylallenes, respectively.
对照:在钯催化下,以对苯醌 (BQ) 作为氧化剂,开发了双(频那醇)二硼 (B 2 pin 2 ) 的丙烯炔高度选择性碳环化/硼化反应。使用 LiOAc⋅2 H 2 O 和 1,2-二氯乙烷 (DCE) 作为溶剂或 BF 3 ⋅Et 2 O 和 THF 分别对于选择性形成硼基化三烯和乙烯基丙二烯至关重要。
Palladium‐Catalyzed Oxidative Carbocyclization–Carbonylation of Allenynes and Enallenes
作者:Chandra M. R. Volla、Javier Mazuela、Jan‐E. Bäckvall
DOI:10.1002/chem.201402688
日期:2014.6.16
A highly efficient oxidativecarbocyclization–carbonylation reaction cascade of allenynes and enallenes has been developed using a PdII salt in low catalytic amounts under ambient temperature and pressure (1 atm of carbon monoxide). The use of DMSO as an additive was found to be important for an efficient reaction. A wide range of alcohols as trapping reagents were used to give the corresponding esters
Palladium-Catalyzed Oxidative Acyloxylation/Carbocyclization of Allenynes
作者:Youqian Deng、Jan-E. Bäckvall
DOI:10.1002/anie.201208718
日期:2013.3.11
New bonds: The title reaction provides access to synthetically useful acyloxylated vinylallenes where a new CC bond, a new CO bond, and a new allene structure are formed. Furthermore, an aerobic version of this transformation was realized using catalytic amounts of p‐benzoquinone (BQ) together with catalytic amounts of cobalt salophen.
新键:标题反应提供了合成有用的酰氧基化乙烯基丙二烯,其中形成了新的 C C 键、新的 C O 键和新的丙二烯结构。此外,使用催化量的对苯醌(BQ)和催化量的钴盐,实现了这种转化的有氧形式。
Palladium-Catalyzed Oxidative Arylating Carbocyclization of Allenynes: Control of Selectivity and Role of H<sub>2</sub>O
for the carbocyclization/arylation of allenynes using arylboronic acids are reported. Arylated vinylallenes are obtained with the use of BF3⋅Et2O as an additive, whereas addition of water leads to arylated trienes. These conditions provide the respective products with excellent selectivities (generally >97:3) for a range of boronic acids and different allenynes. It has been revealed that water plays