Iodothiocyanation/Nitration of Allenes with Potassium Thiocyanate/Silver Nitrite and Iodine
作者:Xiaodong Yang、Yue She、Ya Chong、Huichun Zhai、He Zhu、Baohua Chen、Guosheng Huang、Rulong Yan
DOI:10.1002/adsc.201600304
日期:2016.10.6
Direct strategies for the iodothiocyanation and iodonitration of allenes have been developed. In this process, potassium thiocyanate/silver nitrite and molecular iodine are used as the source of SCN, ONO2 and iodine to provide the desired products in moderate to good yields with high stereoselectivity.
A convenient access to allylic triflones with allenes and triflyl chloride in the presence of (EtO)<sub>2</sub>P(O)H
作者:Jixiang Ni、Yong Jiang、Zhenyu An、Jingfeng Lan、Rulong Yan
DOI:10.1039/c9cc03096d
日期:——
A simple method for the preparation of allylic triflones from allenes and triflyl chloride in the presence of (EtO)2P(O)H has been developed. The features of this reaction are catalyst-free and simple starting substrates. This method tolerates diverse functional groups and substituted allylic triflones are obtained in moderate to good yields.
Catalytic Enantioselective Protoboration of Disubstituted Allenes. Access to Alkenylboron Compounds in High Enantiomeric Purity
作者:Hwanjong Jang、Byunghyuck Jung、Amir H. Hoveyda
DOI:10.1021/ol5022417
日期:2014.9.5
Proto-boryl additions to 1,1-disubstituted allenes in the presence of 1.0–5.0 mol % of chiral NHC–Cu complexes, B2(pin)2, and t-BuOH proceed to afford alkenyl–B(pin) products in up to 98% yield, >98:2 site selectivity, and 98:2 er. The enantiomerically enriched alkenylboron products can be converted to otherwise difficult-to-access alkenyl bromides, methylketones or carboxylic acids. What’s more,
Enantioselective palladium-catalyzed diboration of 1,1-disubstituted allenes
作者:Jiawang Liu、Ming Nie、Qinghai Zhou、Shen Gao、Wenhao Jiang、Lung Wa Chung、Wenjun Tang、Kuiling Ding
DOI:10.1039/c7sc01254c
日期:——
A practical and enantioselectivepalladium-catalyzed diboration of 1,1-disubstituted allenes is developed by employing a P-chiral monophosphorus ligand BI-DIME to form a series of diboronic esters containing a chiral tertiary boronic ester moiety in excellent yields and ee’s with the palladium loading as low as 0.2 mol %. DFT calculations revealed a concerted mechanism of oxidative addition of bis(pinacolato)diboron
通过使用 P-手性单磷配体 BI-DIME 开发了一种实用且对映选择性的钯催化 1,1-二取代丙二烯二硼化反应,以形成一系列含有手性叔硼酸酯部分的二硼酸酯,具有优异的产率和与钯的 ee 值负载量低至 0.2 mol%。DFT 计算揭示了双(频哪醇)二硼和丙二烯插入的氧化加成的协同机制,以及对对映选择性起源的关键分散效应。该方法成功应用于芸苔唑的简洁、对映选择性合成。
Electrophilic cyanation of allylic boranes: synthesis of β,γ-unsaturated nitriles containing allylic quaternary carbon centers
The electrophilic cyanation of allylic boranes, a process that is applicable to the construction of allylic quaternary carbon centers, is reported. The reaction has a broad substrate scope with a high functional group tolerance. The results represent an unprecedented and powerful tool for preparing synthetically useful β,γ-unsaturated nitriles, including derivatives that have been difficult to access