已开发出一种新颖的Brønsted碱体系,用于使用三氯乙酸盐和乙腈对内酯进行非对映选择性二聚。反应一小时后,以高收率(60-93%)获得所需的产物,并且dr> 19:1。另外,通过X射线晶体学分析将主要二聚体的相对立体化学指定为反式。通过使用1 H NMR反应监测确定动力学反应曲线,并揭示了二级整体动力学曲线。此外,通过采用这种方法,链霉菌吡咯烷的官能化类似物的非对映选择性全合成以总产率的65%完成。
(1S)-(−)-N-Monofluoromethylthio-7,7-dichloro-2,10-camphorsultam: An optically pure reagentfor asymmetric monofluoromethylthiolation
作者:He Zhang、Qilong Shen
DOI:10.1016/j.tet.2021.132508
日期:2021.11
The development of an opticallypure monofluoromethylthiolating reagent based on Oppolzer's camphorsultam auxiliary (1S)-(−)-N-monofluoromethylthio-7,7-dichloro-2,10-camphorsultam 1b was described. Reagents 1b reacted with two types of substrates including oxazolone and oxindole derivatives with good to excellent enantioselectivities under mild conditions, thus representing the first available method
描述了基于 Oppolzer 的樟脑磺胺辅助剂 (1S)-(-)- N -monofluoromethylthio-7,7-dichloro-2,10-camphorsultam 1b的光学纯单氟甲硫基化试剂的开发。试剂1b与两种类型的底物反应,包括恶唑酮和羟吲哚衍生物,在温和条件下具有良好到优异的对映选择性,因此代表了我们获得单氟甲基硫醇化立体中心的第一种可用方法。
Asymmetric Difluoromethylthiolation of Carbon Nucleophiles with Optically Pure Difluoromethylthiolating Reagents Derived from Camphorsultam
作者:He Zhang、Xiaolong Wan、Qilong Shen
DOI:10.1002/cjoc.201900298
日期:2019.10
The invention of a family of optically pure electrophilic difluoromethylthiolating reagents 9a–c based on the camphorsultam skeleton was described. These reagents reacted with a variety of soft carbonnucleophiles such as oxazolone, oxindole, benzolactone and β‐ketoester in good to excellent enantioselectivities.
Enantioselective Organocatalytic Addition of Azlactones to Maleimides: A Highly Stereocontrolled Entry to 2,2-Disubstituted-2H-oxazol-5-ones
作者:Andrea-Nekane R. Alba、Guillem Valero、Teresa Calbet、Mercé Font-Bardía、Albert Moyano、Ramon Rios
DOI:10.1002/chem.201000239
日期:2010.8.23
The first highly diastereo‐ and enantioselectiveorganocatalytic synthesis of 2,2‐disubstituted‐2H‐oxazol‐5‐ones is described. The addition of oxazolones to maleimides is promoted by bifunctional thiourea catalysts, which afford the corresponding 2,2‐disubstituted‐2H‐oxazol‐5‐ones with total regio‐ and stereocontrol.