Synthesis of<i>ortho</i>-Hydroxybenzophenones Catalyzed by Magnetically Retrievable Fe<sub>3</sub>O<sub>4</sub>Nanoparticles under Ligand-Free Conditions
作者:Thekkathu Ramani、Paspulati Umadevi、K. Leon Prasanth、Bojja Sreedhar
DOI:10.1002/ejoc.201300909
日期:2013.9
ortho-Benzoylation of phenols with aryl aldehydes to afford the substituted 2-hydroxybenzophenones can be catalyzed efficiently by Fe3O4 nanoparticles underligand-freeconditions. This method is useful for the preparation of xanthones in good yields. The catalyst can be magnetically removed and recycled easily over four cycles without a significant decrease in activity.
OH-Directed Alkynylation of 2-Vinylphenols with Ethynyl Benziodoxolones: A Fast Access to Terminal 1,3-Enynes
作者:Peter Finkbeiner、Ulrich Kloeckner、Boris J. Nachtsheim
DOI:10.1002/anie.201412148
日期:2015.4.13
The first direct alkynylation of 2‐vinylphenols was developed. The rationally optimized hypervalent iodine reagent TIPS‐EBX* in combination with [(Cp*RhCl2)2] as a CH‐activating transition metal catalyst enables the construction of a variety of highly substituted 1,3‐enynes in high yields of up to 98 %. This novel CH activation method shows excellent chemoselectivity and exclusive (Z)‐stereoselectivity
rearrangement of acyl-anion equivalents generated by N-heterocyclic carbene (NHC) catalysis has been achieved. The developed method includes CAr−O, CAr−S, or CAr−N bondcleavage for the formation of a CAr−C bond and enables access to 2-hydroxybenzophenones, an important structural motif that is present in several bioactive natural products. By utilizing this procedure, the alkaloid taxilamine was synthesized
N杂环卡宾(NHC)催化产生的酰基阴离子当量的Truce-Smiles重排已实现。所开发的方法包括裂解C Ar -O,C Ar -S或C Ar -N键以形成C Ar -C键,并能够获得2-羟基二苯甲酮,这是几种生物活性天然存在的重要结构基序产品。通过使用该程序,生物碱紫杉胺分三步合成。DFT计算和控制实验支持经典S NAr机理是与催化剂结合的Meisenheimer型中间体。该方法具有温和的反应条件,出色的官能团耐受性和广泛的底物范围,包括各种类别的(杂)芳烃。
Rhodium-Catalyzed Directing-Group-Assisted Aldehydic C-H Arylations with Aryl Halides
作者:Maddali L. N. Rao、Boddu S. Ramakrishna
DOI:10.1002/ejoc.201700881
日期:2017.9.15
A broad scope for the synthesis of 2′‐substituted benzophenones was established involving directing group (OH or NHTs) assisted C–H arylation of aryl aldehydes with arylhalides under rhodium‐catalyzed conditions.
PdCl2/DABCO-catalyzed direct arylation of 2-hydroxybenzaldehydes in H2O
作者:Najmeh Nowrouzi、Dariush Tarokh
DOI:10.1007/s13738-016-0865-3
日期:2016.8
In this paper the successful application of DABCO both as base and as ligand for efficient coupling reactions of aryl iodides and bromides with 2-hydroxybenzaldehydes in the presence of catalytic amounts of PdCl2 in water as solvent was introduced.