80841-09-4Relevant academic research and scientific papers
Transition-Metal-Free C-C, C-O, and C-N Cross-Couplings Enabled by Light
Liu, Wenbo,Li, Jianbin,Querard, Pierre,Li, Chao-Jun
supporting information, p. 6755 - 6764 (2019/05/06)
Transition-metal-catalyzed cross-couplings to construct C-C, C-O, and C-N bonds have revolutionized chemical science. Despite great achievements, these metal catalysts also raise certain issues including their high cost, requirement of specialized ligands, sensitivity to air and moisture, and so-called "transition-metal-residue issue". Complementary strategy, which does not rely on the well-established oxidative addition, transmetalation, and reductive elimination mechanistic paradigm, would potentially eliminate all of these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols, and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution. Fluorescence spectroscopy and cyclic voltammetry investigations suggest that the interaction between excited acetone and aryl triflate is essential to these couplings. The results in this report are anticipated to provide new opportunities to perform cross-couplings.
Highly potent macrocyclic BACE-1 inhibitors incorporating a hydroxyethylamine core: Design, synthesis and X-ray crystal structures of enzyme inhibitor complexes
Sandgren, Veronica,Agback, Tatiana,Johansson, Per-Ola,Lindberg, Jimmy,Kvarnstr?m, Ingemar,Samuelsson, Bertil,Belda, Oscar,Dahlgren, Anders
supporting information; scheme or table, p. 4377 - 4389 (2012/08/28)
A series of P1-P3 linked macrocyclic BACE-1 inhibitors containing a hydroxyethylamine (HEA) isostere scaffold has been synthesized. All inhibitors comprise a toluene or N-phenylmethanesulfonamide P2 moiety. Excellent BACE-1 potencies, both in enzymatic an
Catalytic diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups
Uyanik, Muhammet,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 5649 - 5652 (2007/10/03)
Highly diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups was catalyzed by tin(IV) chloride (10 mol %). The cyclizations of tert-butyldiphenylsilyl and triisopropylsilyl polyenol ethers gave 4α(equatorial)- and 4β(axial)-siloxypolycycles as major isomers, respectively. The strong nucleophilicity of pro-C(9), a (6E) geometry, and a bulky silyl group effectively favored the 4α-preference, whereas the weak nucleophilicity of pro-C(9), a (6Z)-geometry, and less steric hindrance of a silyl group favored the 4β-preference.
Terphenyl-based helical mimetics that disrupt the p53/HDM2 interaction
Yin, Hang,Lee, Gui-In,Hyung, Soon Park,Payne, Gregory A.,Rodriguez, Johanna M.,Sebti, Said M.,Hamilton, Andrew D.
, p. 2704 - 2707 (2007/10/03)
(Chemical Equation Presented) HDM2 regulates p53 by binding to its transactivation domain and promoting its ubiquitin-dependent degradation. Crystallographic analysis of the HDM2/p53 complex revealed that three hydrophobic residues (F19, W23, L26) along one face of the p53 helical peptide are essential for binding (see picture). Terphenyl-based antagonists mimic the α-helical region of p53 and disrupt HDM2/p53 complexation.
Ring expansion-annulation strategy for the synthesis of substituted azulenes and oligoazulenes. 2. Synthesis of azulenyl halides, sulfonates, and azulenylmetal compounds and their application in transition-metal-mediated coupling reactions
Crombie, Aimee L.,Kane Jr., John L.,Shea, Kevin M.,Danheiser, Rick L.
, p. 8652 - 8667 (2007/10/03)
A "ring expansion-annulation strategy" for the synthesis of substituted azulenes is described based on the reaction of β'-bromo- α-diazo ketones with rhodium carboxylates. The key transformation involves an intramolecular Buechner reaction followed by β-elimination of bromide, tautomerization, and in situ trapping of the resulting 1-hydroxyazulene as a carboxylate or triflate ester. Further synthetic elaboration of the azulenyl halide and sulfonate annulation products can be achieved by employing Heck, Negishi, Stille, and Suzuki coupling reactions. Reaction of the azulenyl triflate 84 with pinacolborane provides access to the azulenylboronate 91, which participates in Suzuki coupling reactions with alkenyl and aryl iodides. The application of these coupling reactions to the synthesis of biazulenes, terazulene 101, and related oligoazulenes is described, as well as the preparation of the azulenyl amino acid derivative 110.
A ring expansion-annulation strategy for the synthesis of substituted azulenes. Preparation and suzuki coupling reactions of 1-azulenyl triflates
John L Jr., Kane,Shea, Kevin M.,Crombie, Aimee L.,Danheiser, Rick L.
, p. 1081 - 1084 (2007/10/03)
(matrix presented) A new strategy for the synthesis of substituted azulenes is reported, based on the reaction of β′-bromo-α-diazo ketones with rhodium carboxylates The key transformation involves intramolecular addition of a rhodium carbenoid to an arene π-bond, electrocyclic ring opening, β-elimination, tautomerization, and trapping to produce 1-hydroxyazulene derivatives. The synthetic utility of the method is enhanced by the ability of the triflate derivatives to participate in Suzuki coupling reactions, as illustrated in a synthesis of the antiulcer drug egualen sodium (KT1-32).
Structure-based design of N-phenyl phenoxazine transthyretin amyloid fibril inhibitors
Petrassi, H. Michael,Klabunde, Thomas,Sacchettini, James,Kelly, Jeffery W.
, p. 2178 - 2192 (2007/10/03)
Starting with the published 2.0 A X-ray crystal structure of the transthyretin.(flufenamic acid)2 complex, a simple structure-based ligand design strategy was employed to conceive of N-phenyl phenoxazine transthyretin (TTR) amyloid fibril inhib
Structure-based design of COX-2 selectivity into flurbiprofen
Bayly, Christopher I.,Black, W. Cameron,Leger, Serge,Ouimet, Nathalie,Ouellet, Marc,Percival, M. David
, p. 307 - 312 (2007/10/03)
Comparative computer modeling of the X-ray crystal structures of cyclooxygenase isoforms COX-1 and COX-2 has led to the design of COX-2 selectivity into the nonselective inhibitor flurbiprofen. The COX-2 modeling was based on a postulated binding mode for flurbiprofen and took advantage of a small alcove in the COX-2 active site created by different positions of the Leu384 sidechain between COX-1 and COX-2. The design hypothesis was tested by synthesis and biological assay of a series of flurbiprofen analogs, culminating in the discovery of several inhibitors having up to 78-fold selectivity for COX-2 over COX-1.
