Expeditious Approach to Pyrrolophenanthridones, Phenanthridines, and Benzo[<i>c</i>]phenanthridines via Organocatalytic Direct Biaryl-Coupling Promoted by Potassium<i>tert</i>-Butoxide
作者:Subhadip De、Sourabh Mishra、Badrinath N. Kakde、Dhananjay Dey、Alakesh Bisai
DOI:10.1021/jo400890k
日期:2013.8.16
intramolecular homolytic aromatic substitution (HAS). Interestingly, this biaryl coupling also works in the presence of potassium tert-butoxide as sole promoter. On extending our approach further, we found that N-acyl 2-bromo-N-arylbenzylamines undergo a one-pot N-deprotection/biaryl coupling followed by oxidation, thus offering an expeditious route to the phenanthridine and benzo[c]phenanthridine skeletons. The
在叔丁醇钾和有机分子作为催化剂存在的情况下,已经开发出一种涉及邻卤代N芳基苄胺的“无过渡金属”分子内联芳基偶合的方法。该反应似乎通过KO t Bu促进的分子内均溶芳族取代(HAS)进行。有趣的是,这种联芳基偶合在叔丁醇钾作为唯一促进剂的情况下也起作用。在进一步扩展我们的方法时,我们发现N-酰基2-溴-N-芳基苄胺经历了一锅N-脱保护/联芳基偶联,然后进行氧化,因此提供了通往菲啶和苯并[ c ]菲啶骨架的快速途径。该策略已被应用于简明的金莲花科生物碱的合成。oxoassoanine(1B),anhydrolycorinone(1D),5,6- dihydrobicolorine(2D),trispheridine(2B),和苯并[ C ^ ]菲啶生物碱dihydronitidine(图3b),dihydrochelerythidine(3D),dihydroavicine(3F),norni
Switching between mono and doubly reduced odd alternant hydrocarbon: designing a redox catalyst
作者:Jasimuddin Ahmed、Paramita Datta、Arpan Das、Stephy Jomy、Swadhin K. Mandal
DOI:10.1039/d0sc05972b
日期:——
orbital (HMO) calculations in 1950, it has been well known that the odd alternant hydrocarbon (OAH), the phenalenyl (PLY) system, can exist in three redox states: closed shell cation (12π e−), mono-reduced open shell neutral radical (13π e−) and doubly reduced closed shell anion (14π e−). Switching from one redox state of PLY to another leads to a slight structural change owing to its low energy of disproportionation
Intramolecular Direct Dehydrohalide Coupling Promoted by KO<sup><i>t</i></sup>Bu: Total Synthesis of <i>Amaryllidaceae</i> Alkaloids Anhydrolycorinone and Oxoassoanine
作者:Subhadip De、Santanu Ghosh、Subhajit Bhunia、Javeed Ahmad Sheikh、Alakesh Bisai
DOI:10.1021/ol3019677
日期:2012.9.7
substitution (HAS) with aryl radicals has been developed in the presence of potassium tert-butoxide and an organic molecule as the catalyst. The methodology has been applied to a concisesynthesis of Amaryllidaceae alkaloids viz. oxoassoanine (1b), anhydrolycorinone (1d), and other related structures. Interestingly, the method also works only in the presence of potassium tert-butoxide.