1026-81-9Relevant articles and documents
Diarylated ethanones from Mo(CO)6-mediated and microwave-assisted palladium-catalysed carbonylative Negishi cross-couplings
Motwani, Hitesh V.,Larhed, Mats
, p. 4729 - 4733 (2013)
Two protocols for palladium-catalysed carbonylative Negishi cross-couplings were developed for aryl iodides and aryl bromides. The two main breakthroughs were that molybdenum hexacarbonyl [Mo(CO)6] could be used as a solid in situ source of CO, and that controlled microwave irraditaion could be used for heating. Consequently, the reactions were safe (in contrast to when CO gas was used) and fast (in comparison to when conventional heating was used). The carbonylative cross-coupling reactions were carried out using commercially available benzylzinc bromide in closed vials (90-120°C for 0.5-1 h) to give a set of diarylated ethanones, a common pharmacophore found in several pharmaceuticals, in moderate to high isolated yields (47-84 %). The mild three-component carbonylation protocol presented here is operationally simple, safe, and rapid, and the formation of the carbonylative Negishi cross-coupling product is favoured over the product of Negishi cross-coupling. Copyright
Benzylic aroylation of toluenes with unactivated tertiary benzamides promoted by directed ortho-lithiation
Bao, Can-Can,Luo, Yan-Long,Du, Hui-Zhen,Guan, Bing-Tao
, p. 1349 - 1354 (2021/07/12)
The deprotonative functionalization of toluenes, for their weak acidity, generally needs strong bases, thus leading to the requirement of harsh conditions and the generation of by-products. Direct nucleophilic acyl substitution reaction of amides with organometallic reagents could provide an ideal solution for ketone synthesis. However, the inert amides and highly reactive organometallic reagents bring great challenges for an efficient and selective synthetic approach. Herein, we reported an lithium diisopropylamide (LDA)-promoted benzylic aroylation of toluenes with unactivated tertiary benzamides, providing a direct and efficient synthesis of various aryl benzyl ketones. This process features a kinetic deprotonative functionalization of toluenes with a readily available base LDA. Mechanism studies revealed that the directed ortho-lithiation of the tertiary benzamide with LDA promoted the benzylic kinetic deprotonation of toluene and triggered the nucleophilic acyl substitution reaction with the amide. [Figure not available: see fulltext.].
