13351-61-6Relevant articles and documents
Diradicals Photogeneration from Chloroaryl-Substituted Carboxylic Acids
Di Terlizzi, Lorenzo,Protti, Stefano,Ravelli, Davide,Fagnoni, Maurizio
, (2022/04/09)
With the aim of generating new, thermally inaccessible diradicals, potentially able to induce a double-strand DNA cleavage, the photochemistry of a set of chloroaryl-substituted carboxylic acids in polar media was investigated. The photoheterolytic cleavage of the Ar?Cl bond occurred in each case to form the corresponding triplet phenyl cations. Under basic conditions, the photorelease of the chloride anion was accompanied by an intramolecular electron-transfer from the carboxylate group to the aromatic radical cationic site to give a diradical species. This latter intermediate could then undergo CO2 loss in a structure-dependent fashion, according to the stability of the resulting diradical, or abstract a hydrogen atom from the medium. In aqueous environment at physiological pH (pH=7.3), both a phenyl cation and a diradical chemistry was observed. The mechanistic scenario and the role of the various intermediates (aryl cations and diradicals) involved in the process was supported by computational analysis.
A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
Kaicharla, Trinadh,Ngoc, Trung Tran,Teichert, Johannes F.,Tzaras, Dimitrios-Ioannis,Zimmermann, Birte M.
supporting information, p. 16865 - 16873 (2021/10/20)
Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft"copper(I) hydrides to previously unreactive "hard"ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
Metal-Free Enantioselective Oxidative Arylation of Alkenes: Hypervalent-Iodine-Promoted Oxidative C?C Bond Formation
Shimogaki, Mio,Fujita, Morifumi,Sugimura, Takashi
supporting information, p. 15797 - 15801 (2016/12/16)
The enantioselective oxyarylation of (E)-6-aryl-1-silyloxylhex-3-ene was achieved using a lactate-based chiral hypervalent iodine(III) reagent in the presence of boron trifluoride diethyl etherate. The silyl ether promotes the oxidative cyclization, and enhances the enantioselectivity. In addition, the corresponding aminoarylation was achieved.
Structure-activity relationship studies of S1P agonists with a dihydronaphthalene scaffold
Kurata, Haruto,Kusumi, Kensuke,Otsuki, Kazuhiro,Suzuki, Ryo,Kurono, Masakuni,Tokuda, Natsuko,Takada, Yuka,Shioya, Hiroki,Mizuno, Hirotaka,Komiya, Takaki,Ono, Takeji,Hagiya, Hiroshi,Minami, Masashi,Nakade, Shinji,Habashita, Hiromu
scheme or table, p. 144 - 148 (2012/02/16)
Structure-activity relationship (SAR) of sphingosine-1-phosphate receptor agonists with a dihydronaphthalene scaffold was investigated. Compound 1 was modified to improve S1P1 agonistic activity and in vivo peripheral lymphocyte lowering (PLL) activity without impairing selectivity over S1P 3 agonistic activity. A detailed SAR study of the terminal lipophilic part revealed that the introduction of substituents on the propylene linker and the terminal benzene ring influences in vitro and PLL activities. Compound 6n bearing a (S)-methyl group at the 2-position on the propylene linker and chlorine at the para-position on the terminal benzene ring showed potent hS1P1 agonistic activity with excellent selectivity over hS1P 3 and in vivo PLL activity in mice.
Nickel(0)/NaHMDS adduct-mediated intramolecular alkylation of unactivated arenes via a homolytic aromatic substitution mechanism
Beaulieu, Louis-Philippe B.,Roman, Daniela Sustac,Vallee, Frederic,Charette, Andre B.
, p. 8249 - 8251 (2012/09/07)
A variety of polycycles can be synthesized via an intramolecular alkylation cyclization promoted by Ni(PPh3)4 and NaHMDS. Mechanistic investigations support the catalytic nature of Ni0 in the course of TEMPO scavenging experiments and its association with the substrate and NaHMDS to form an adduct by DOSY NMR.
A fast and practical approach to tetrahydropyranylation and depyranylation of alcohols using indium triflate
Mineno, Tomoko
, p. 7975 - 7978 (2007/10/03)
Indium triflate-mediated tetrahydropyranylation of alcohols in dichloromethane and depyranylation of these products in aqueous methanol utilizing the same reagent but different molar ratio is described. In addition, indium triflate-promoted conversion of tetrahydropyran ethers to their corresponding acetates has also been described.
Indium-mediated chemoselective deprotection of trichloroethoxycarbonyl and trichloroacetyl groups
Valluri, Muralikrishna,Mineno, Tomoko,Hindupur, Rama M.,Avery, Mitchell A.
, p. 7153 - 7154 (2007/10/03)
A new, mild, and chemoselective method for the deprotection of trichloroethoxylcarbonyl and trichloroacetyl groups is described.
Nickel-Mediated Cross-Coupling of Unactivated Neopentyl Iodides with Organozincs
Park, Kwangyong,Yuan, Kaixu,Scott, William J.
, p. 4866 - 4870 (2007/10/02)
(dppf)NiCl2 catalyzes the cross-coupling of unactivated primary neopentyl iodides with diorganozinc reagents.The zinc nucleophiles are formed by the treatment of ZnCl2*dioxane with 2 mol equiv of a Grignard reagent in an etheral solvent.The cross-coupling works optimally for diorganozincs formed from aryl chlorides or CH3MgCl.Use of aryl bromides can cause reduction and/or reductive dimerization of the electrophile.The analogous reaction with (CH3)2CuMgCl in either the presence or the absence of Group 10 metal catalysts failed to afford reasonable yields of cross-coupled products.The diorganozinc methodology overcomes many of the side reactions observed with the (dppf)NiCl2-mediated cross-coupling of Grignard reagents.
Practical hydroxymethylation of aldehydes and ketones via pinacol cross-coupling reactions with paraformaldehyde
Park, Jeonghan,Pedersen, Steven F.
, p. 2069 - 2080 (2007/10/02)
A general and practical method for the direct hydroxymethylation of aldehydes and ketones via pinacol cross-coupling with paraformaldehyde is described. The reaction is promoted by vanadium(II) ions which are conveniently generated from the reduction of VCl3(THF)3 with zinc dust. Excellent yields of terminal diols are obtained and stereoselective coupling is observed with some chiral aldehydes and ketones.
