Direct Pd-Catalyzed Cross-Coupling of Functionalized Organoaluminum Reagents
作者:Klaus Groll、Tobias D. Blümke、Andreas Unsinn、Diana Haas、Paul Knochel
DOI:10.1002/anie.201205987
日期:2012.10.29
A handsome couple: Through the use of the simple Pd catalyst [Pd(tmpp)2Cl2] (tmpp=tris(2,4,6‐trimethoxyphenyl)phosphine) and THF/DMF as solvent, various aryl‐, heteroaryl‐, benzyl‐ and alkylaluminum reagents can be readily cross‐coupled with aryl or heteroaryl iodides, bromides, and nonaflates, and in special cases even with chlorides and triflates. This cross‐coupling tolerates free NH2 groups, aldehydes
in good to high yields by coupling N-tosylhydrazones (NTHs) with benzylic phosphates as electrophilic partners. The obtained new catalytic system consisted of PdCl2(CH3CN)2/dppp, LiOtBu as a base, and cyclopentyl methyl ether as a green solvent. In addition, we performed a gram-scale transformation using NTH derivatives and benzylic phosphates having a C sp2–Cl bond. The latter was used as a starting
该研究表明,通过将N-甲苯磺酰腙 (NTH) 与磷酸苄基作为亲电伙伴偶联,可以以良好至高产率获得各种具有高化学选择性的二取代和三取代烯烃。得到的新型催化体系由PdCl 2 (CH 3 CN) 2 /dppp、LiO t Bu为碱、环戊基甲基醚为绿色溶剂组成。此外,我们使用 NTH 衍生物和具有 C sp 2 -Cl 键的苄基磷酸酯进行了克级转化。后者被用作关键中间体进一步后功能化的起点。
Continuous Visible‐Light Photoflow Approach for a Manganese‐Catalyzed (Het)Arene C−H Arylation
Manganese photocatalysts enabled versatile room‐temperatureC−H arylation reactions by means of continuous visible‐light photoflow, thus allowing for efficient C−H arylations in 30 minutes with ample scope. The robustness of the manganese‐catalyzed photoflow strategy was shown by visiblelight‐induced gram‐scale synthesis, clearly outperforming the batch performance.
An array of useful N,N′-ethylene-bridged bispyrazole derivatives were achieved with moderate-to-good yields via the electrochemical alkenyl diazolation reaction with no external chemical oxidant or metal catalyst. Critical to this successful process is the usage of anodal direct oxidation, which ensured sufficient activation of alkenes to allow engagement with two equivalents of pyrazoles. The tri-