6555-30-2Relevant academic research and scientific papers
C(sp3)-H methylation enabled by peroxide photosensitization and Ni-mediated radical coupling
Vasilopoulos, Aristidis,Krska, Shane W.,Stahl, Shannon S.
, p. 398 - 403 (2021/05/06)
The “magic methyl” effect describes the change in potency, selectivity, and/or metabolic stability of a drug candidate associated with addition of a single methyl group. We report a synthetic method that enables direct methylation of C(sp3)-H bonds in diverse drug-like molecules and pharmaceutical building blocks. Visible light-initiated triplet energy transfer promotes homolysis of the O-O bond in di-tert-butyl or dicumyl peroxide under mild conditions. The resulting alkoxyl radicals undergo divergent reactivity, either hydrogen-atom transfer from a substrate C-H bond or generation of a methyl radical via b-methyl scission. The relative rates of these steps may be tuned by varying the reaction conditions or peroxide substituents to optimize the yield of methylated product arising from nickel-mediated cross-coupling of substrate and methyl radicals.
Ligand-Controlled Regiodivergence in Nickel-Catalyzed Hydroarylation and Hydroalkenylation of Alkenyl Carboxylic Acids**
Deng, Ruohan,Engle, Keary M.,Fu, Yue,Gao, Yang,Li, Zi-Qi,Liu, Peng,Tran, Van T.
supporting information, p. 23306 - 23312 (2020/10/19)
A nickel-catalyzed regiodivergent hydroarylation and hydroalkenylation of unactivated alkenyl carboxylic acids is reported, whereby the ligand environment around the metal center dictates the regiochemical outcome. Markovnikov hydrofunctionalization products are obtained under mild ligand-free conditions, with up to 99 % yield and >20:1 selectivity. Alternatively, anti-Markovnikov products can be accessed with a novel 4,4-disubstituted Pyrox ligand in excellent yield and >20:1 selectivity. Both electronic and steric effects on the ligand contribute to the high yield and selectivity. Mechanistic studies suggest a change in the turnover-limiting and selectivity-determining step induced by the optimal ligand. DFT calculations reveal that in the anti-Markovnikov pathway, repulsion between the ligand and the alkyl group is minimized (by virtue of it being 1° versus 2°) in the rate- and regioselectivity-determining transmetalation transition state.
Two-carbon ring expansion of 1-indanones via insertion of ethylene into carbon-carbon bonds
Xia, Ying,Ochi, Shusuke,Dong, Guangbin
, p. 13038 - 13042 (2019/08/26)
A rhodium-catalyzed direct insertion of ethylene into a relatively unstrained carbon-carbon bond in 1-indanones is reported, which provides a two-carbon ring expansion strategy for preparing seven-membered cyclic ketones. As many 1-indanones are commercially available and ethylene is inexpensive, this strategy simplifies synthesis of benzocycloheptenones that are valuable synthetic intermediates for bioactive compounds but challenging to prepare otherwise. In addition, the reaction is byproduct-free, redox neutral, and tolerant of a wide range of functional groups, which may have implications on unconventional strategic bond disconnections for preparing complex cyclic molecules.
One-pot, solvent-free Pd(II)-catalyzed direct β-C-H arylation of carboxamides involving anhydrides as substrates via in situ installation of directing group
Dalal, Arup,Singh, Prabhakar,Babu, Srinivasarao Arulananda
, p. 1246 - 1257 (2019/01/30)
A one-pot, multicomponent-type, solvent-free Pd(II)-catalyzed direct β-C-H activation/arylation of carboxamides involving anhydrides as substrates via in situ installation of directing group (DG) is reported. Typically, the DG-assisted β-C-H activation/ar
ANTI-HCMV COMPOSITIONS AND METHODS
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, (2016/06/06)
This document relates to compounds useful as agents for preventing or treating human cytomegalovirus (HCMV) infections.
Facile palladium-catalyzed hydrocarboxylation of olefins without external CO gas
Wang, Yang,Ren, Wenlong,Li, Jingfu,Wang, Haining,Shi, Yian
supporting information, p. 5960 - 5963 (2015/02/19)
An effective Pd-catalyzed hydrocarboxylation of olefins with phenyl formate and formic acid is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under operationally simple conditions without the use of toxic CO gas.
Lipase catalysed kinetic resolutions of 3-aryl alkanoic acids
Deasy, Rebecca E.,Brossat, Maude,Moody, Thomas S.,Maguire, Anita R.
experimental part, p. 47 - 61 (2011/04/18)
Hydrolase catalysed kinetic resolutions leading to a series of 3-aryl alkanoic acids (≥94% ee) are described. Hydrolysis of the ethyl esters with a series of hydrolases was undertaken to identify biocatalysts that yield the corresponding acids with excellent enantiopurity in each case. Steric and electronic effects on the efficiency and enantioselectivity of the biocatalytic transformation were also explored.
INDANE COMPOUNDS
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Page/Page column 12; 24, (2009/05/28)
This invention provides new indane compounds, their use for the treatment or prevention of melatoninergic disorders and its compositions.
Dynamic equilibria in the products of intramolecular buchner additions of diazoketones to aryl rings bearing methoxy substituents
Maguire,O'Leary,Harrington,Lawrence,Blake
, p. 7166 - 7177 (2007/10/03)
Rhodium carboxylate catalyzed aromatic addition reactions of a range of diazoketones bearing methoxy-substituted aryl rings have been explored. While the existence of norcaradiene-cycloheptatriene equilibria in related compounds is well established, the aromatic addition products in this study display more complex dynamic equilibria due to conjugation with the methoxy group; the experimental evidence for this is discussed in detail. In the azulenone products 21-26 derived from p-methoxy-substituted diazoketones 14-16, the diastereomers interconvert via a spiro intermediate 39. A related mechanistic process in the azulenones 43-46 derived from the o-methoxy-substituted diazoketones 17, 18 interconverts regioisomers, explaining the conflicting reports for the regioselectivity of the cyclization of diazoketone 1. With the m-methoxy-substituted diazoketone 19, involvement of the methoxy group through a different pathway results in fragmentation of the azulenone to form the tetralone 47. With the azulenones 21-26 exclusive trapping of the norcaradiene associated with the less thermodynamically stable diastereomers in a cycloadduct with N-phenylmaleimide is observed. Due to the presence of the activating methoxy substituent on the aromatic ring, the aromatic addition reactions of the diazoketones studied were not very sensitive to the nature of the rhodium catalyst.
Studies on the Liverwort Sesquiterpene Alcohol Tamariscol. Synthesis and Absolute Configuration
Tori, Motoo,Sono, Masakazu,Nishigaki, Yukiko,Nakashima, Katsuyuki,Asakawa, Yoshinori
, p. 435 - 445 (2007/10/02)
The relative configuration of the liverwort sesquiterpene alcohol (-)-tamariscol 1 has been confirmed by total synthesis and the absolute configuration has been established from the CD spectrum of the hydrindanone degradation product from (-)-1.
