186583-59-5Relevant academic research and scientific papers
Pd-Catalyzed ipso, meta-Dimethylation of ortho-Substituted Iodoarenes via a Base-Controlled C-H Activation Cascade with Dimethyl Carbonate as the Methyl Source
Wu, Zhuo,Wei, Feng,Wan, Bin,Zhang, Yanghui
supporting information, p. 4524 - 4530 (2021/05/04)
A methyl group can have a profound impact on the pharmacological properties of organic molecules. Hence, developing methylation methods and methylating reagents is essential in medicinal chemistry. We report a palladium-catalyzed dimethylation reaction of ortho-substituted iodoarenes using dimethyl carbonate as a methyl source. In the presence of K2CO3 as a base, iodoarenes are dimethylated at the ipso- and meta-positions of the iodo group, which represents a novel strategy for meta-C-H methylation. With KOAc as the base, subsequent oxidative C(sp3)-H/C(sp3)-H coupling occurs; in this case, the overall transformation achieves triple C-H activation to form three new C-C bonds. These reactions allow expedient access to 2,6-dimethylated phenols, 2,3-dihydrobenzofurans, and indanes, which are ubiquitous structural motifs and essential synthetic intermediates of biologically and pharmacologically active compounds.
Transition-Metal-Free Decarboxylative Iodination: New Routes for Decarboxylative Oxidative Cross-Couplings
Perry, Gregory J. P.,Quibell, Jacob M.,Panigrahi, Adyasha,Larrosa, Igor
supporting information, p. 11527 - 11536 (2017/08/30)
Constructing products of high synthetic value from inexpensive and abundant starting materials is of great importance. Aryl iodides are essential building blocks for the synthesis of functional molecules, and efficient methods for their synthesis from chemical feedstocks are highly sought after. Here we report a low-cost decarboxylative iodination that occurs simply from readily available benzoic acids and I2. The reaction is scalable and the scope and robustness of the reaction is thoroughly examined. Mechanistic studies suggest that this reaction does not proceed via a radical mechanism, which is in contrast to classical Hunsdiecker-type decarboxylative halogenations. In addition, DFT studies allow comparisons to be made between our procedure and current transition-metal-catalyzed decarboxylations. The utility of this procedure is demonstrated in its application to oxidative cross-couplings of aromatics via decarboxylative/C-H or double decarboxylative activations that use I2 as the terminal oxidant. This strategy allows the preparation of biaryls previously inaccessible via decarboxylative methods and holds other advantages over existing decarboxylative oxidative couplings, as stoichiometric transition metals are avoided.
Gold(I)-catalyzed iodination of arenes
Leboeuf, David,Ciesielski, Jennifer,Frontier, Alison J.
supporting information, p. 399 - 402 (2014/03/21)
A wide variety of electron-rich arenes were efficiently converted into the corresponding iodinated compounds via a gold(I)-catalyzed reaction under mild conditions. Georg Thieme Verlag Stuttgart. New York.
Synthesis of cell-permeable stapled BH3 peptide-based Mcl-1 inhibitors containing simple aryl and vinylaryl cross-linkers
Muppidi, Avinash,Doi, Kenichiro,Ramil, Carlo P.,Wang, Hong-Gang,Lin, Qing
, p. 7740 - 7745 (2014/12/10)
We report the synthesis of a series of distance-matching aryl and vinylaryl cross-linkers for constructing stapled peptides containing cysteines at i,i+7 positions. Langevin dynamics simulation studies helped to classify these cross-linkers into two categories: the rigid cross-linkers with narrower S-S distance distribution and the flexible cross-linkers with wider S-S distance distribution. The stapled Noxa BH3 peptides with the flexible distance-matching cross-linkers gave the highest degree of helicity as well as the most potent inhibitory activity against Mcl-1. However, the stapled peptides with the highest hydrophobicity showed the most efficient cellular uptake. Together, this work illustrates the divergent nature of binding affinity and cellular uptake, and the vital importance of choosing appropriate cross-linkers in constructing stapled peptides with the drug-like properties.
Stable axial chirality in metal complexes bearing 4,4′-substituted BIPHEPs: Application to catalytic asymmetric carbon-carbon bond-forming reactions
Aikawa, Kohsuke,Miyazaki, Yoshitaka,Mikami, Koichi
, p. 201 - 208 (2012/04/23)
Not only electronic but also steric effects of 4,4′-substituents in BIPHEP derivatives and metal (Pd, Pt, and Au) complexes are shown to influence the stability of the biphenyl single bond rotation. While electron-donating or sterically demanding substituents on the 4,4′-positions destabilize the axial chirality of BIPHEP derivatives, electron-withdrawing or sterically less demanding ones on the 4,4′-positions stabilize the axis chirality. Particularly, the axial chirality of palladium dichloride complexes bearing BIPHEP with t-Bu and CF3 substituents on the 4,4′-positions is most labile and stable, respectively (ΔG≠ = 29.22 and 30.49 kcal mol-1 at 300 K; t1/2 = 7 and 56 years at 300 K). These enantiopure dicationic BIPHEPPd complexes can be employed for catalytic enantioselective arylation, alkenylation, and ene reactions to give the corresponding products in good-to-excellent yields and enantioselectivities. Significantly, in the carbonyl-ene reaction of trifluoropyruvate with isobutene, the turnover frequency (TOF) reached 58200 h-1. The remarkable effects of 4,4′-substituents in BIPHEP derivatives can be employed as a guiding principle in the design of versatile and efficient ligands.
Efficient and diversity-oriented total synthesis of Riccardin C and application to develop novel macrolactam derivatives
Iwashita, Masazumi,Fujii, Shinya,Ito, Shigeru,Hirano, Tomoya,Kagechika, Hiroyuki
experimental part, p. 6073 - 6082 (2011/08/22)
Riccardin C (RC, 1) is a macrocyclic bis(bibenzyl) natural product exhibiting remarkable biological activity as a nuclear liver X receptors (LXRs) ligand and a lipid metabolism mediator. RC is expected to be a lead compound to develop drugs for atherosclerotic diseases, and therefore exploiting diversity-oriented synthesis of RC is a promising approach to drug discovery. In this paper, we report novel total synthesis of RC (7.4% overall yield in 16 steps) by using the intramolecular SNAr reaction as key cyclization reaction. This is the first example of efficient macrocyclization using 3-nitro-4-fluorostilbene as an electrophile. The methodology could be applied to synthesize novel lactam analogs of RC. The diversity-oriented synthesis of RC is versatile method for the synthesis of various types of bis(bibenzyl) natural products and their derivatization.
Simple method for the introduction of iodo-label on (3-trifluoromethyl) phenyldiazirine for photoaffinity labeling
Hashimoto, Makoto,Kato, Yuhi,Hatanaka, Yasumaru
, p. 3391 - 3394 (2007/10/03)
A simple and mild method was developed for the introduction of iodo-label on (3-trifluoromethyl) phenyldiazirine (TPD) aromatic ring in the presence of three membered diazirine ring. An iodination protocol, I2-BTI in CH3CN, was found
Synthesis of the spirocyclic cyclohexadienone ring system of the schiarisanrins.
Coleman,Guernon,Roland
, p. 277 - 280 (2007/10/03)
[structure: see text] Studies on the synthesis of the spirocyclic cyclohexadienone ring system 2 of the schiarisanrin family of natural products 1 are described and were based on the Lewis acid-promoted C-alkylation of the corresponding phenolic precursor.
Electrophilic aromatic thallation of phenol ethers: an improved experimental procedure
Santos, M. L. dos,Magalhaes, G. C. de,Filho, R. Braz
, p. 15 - 20 (2007/10/03)
In this report we present a simple modification of the classical electrophilic aromatic thallation reaction, in which iodination of several phenol ethers can be achieved in high yields under very mild reaction conditions with the mixture TTFA/BF3.Et2O/ClCH2CH2Cl, whereby both oxidative dimerizations and hydrolysis have been succesfully suppressed. - Keywords: Thallium; Electrophilic thallation; Electron-rich arenes; Aryl; Phenol
