- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
-
An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
-
supporting information
p. 7445 - 7449
(2021/10/02)
-
- Light-induced Ligation of o-Quinodimethanes with Gated Fluorescence Self-reporting
-
We introduce a highly efficient photoligation system, affording a pro-fluorescent Diels-Alder product that, on demand, converts into an intensively fluorescent naphthalene via E1 elimination in the presence of catalytic amounts of acid. The Diels-Alder reaction of the photocaged diene (o-quinodimethane ether or thioether) with electron-deficient alkynes is induced by UV or visible light. In contrast to previously reported ligation techniques directly leading to fluorescent products, the fluorescence is turned on after the photoligation. Thus, the light absorption of the fluorophore does not undermine the photoligation via competitive absorption, and as a result, photobleaching or side reactions of the fluorophore are not observed. Critically, the gated generation of a fluorescent product allows for fluorometric determination of the conversion. We employ a simple synthesis strategy for heterobifunctional electron-deficient alkynes allowing for facile functionalization of payload molecules.
- Feist, Florian,Rodrigues, Leona L.,Walden, Sarah L.,Krappitz, Tim W.,Dargaville, Tim R.,Weil, Tanja,Goldmann, Anja S.,Blinco, James P.,Barner-Kowollik, Christopher
-
supporting information
p. 7744 - 7748
(2020/05/22)
-
- Selective Palladium(II)-Catalyzed Carbonylation of Methylene β-C?H Bonds in Aliphatic Amines
-
Palladium(II)-catalyzed C?H carbonylation reactions of methylene C?H bonds in secondary aliphatic amines lead to the formation of trans-disubstituted β-lactams in excellent yields and selectivities. The generality of the C?H carbonylation process is aided by the action of xantphos-based ligands and is important in securing good yields for the β-lactam products.
- Cabrera-Pardo, Jaime R.,Trowbridge, Aaron,Nappi, Manuel,Ozaki, Kyohei,Gaunt, Matthew J.
-
p. 11958 - 11962
(2017/09/20)
-
- Regiospecific synthesis of substituted 2-nitrobenzaldehydes from benzaldehydes through palladium-catalyzed chelation-assisted C-H nitration
-
A regiospecific synthesis of substituted 2-nitrobenzaldehydes from substituted benzaldehydes has been developed that involves a three-step process with palladium-catalyzed chelation-assisted C-H nitration as the key step. In the process, O-methyl aldoxime serves as a removable directing group for the palladium-catalyzed ortho-nitration of substituted benzaldoximes and it can be removed in subsequent conversion of the resulting 2-nitrobenzaldoximes into 2-nitrobenzaldehydes.
- Zhang, Wei,Wu, Degui,Zhang, Jian,Liu, Yunkui
-
p. 5827 - 5835
(2014/10/15)
-
- Synthesis and computational analysis of densely functionalized triazoles using o -nitrophenylalkynes
-
Dipolar cylcoadditions with azides using a series of o-nitrophenylethynes and disubstituted alkynes were studied experimentally and computationally. Density functional theory computations reveal the steric and electronic parameters that control the regios
- McIntosh, Melissa L.,Johnston, Ryne C.,Pattawong, Ommidala,Ashburn, Bradley O.,Naffziger, Michael R.,Cheong, Paul Ha-Yeon,Carter, Rich G.
-
p. 1101 - 1112
(2012/03/11)
-
- A highly selective tandem cross-coupling of gem-dihaloolefins for a modular, efficient synthesis of highly functionalized indoles
-
(Chemical Equation Presented) A highly efficient method of indole synthesis using gem-dihalovinylaniline substrates and an organoboron reagent was developed via a Pd-catalyzed tandem intramolecular amination and an intermolecular Suzuki coupling. Aryl, alkenyl, and alkyl boron reagents are all successfully employed, making for a versatile modular approach. The reaction tolerates a variety of substitution patterns on the aniline leading to indoles with group at C2-C7. The orthogonal approach of the sequential copper- and palladium-mediated synthesis of 1,2-diarylindoles exploited the wide availability of diverse organoboron reagents.
- Fang, Yuan-Qing,Lautens, Mark
-
p. 538 - 549
(2008/09/17)
-
- BICYCLIC DERIVATIVES AS PPAR MODULATORS
-
The present invention is directed to compounds represented by the following structural formula, Formula (I), and stereoisomers, pharmaceutically acceptable salts, solvates and hydrates thereof, wherein: (a) R2 is selected from the group consisting of C0-C8 alkyl and C1-4- heteroalkyl; (b) X is selected from the group consisting of a single bond, O, S, S(O)2 and N; (c) U is an aliphatic linker wherein one carbon atom of the aliphatic linker is optionally replaced with O, NH or S, and wherein such aliphatic linker is optionally substituted with from one to four substituents each independently selected from R30; (d) Y is selected from the group consisting of C, O, S, NH and a single bond; and (e) E is C(R3)(R4)A or A.
- -
-
Page/Page column 100
(2008/06/13)
-
- Method and novel intermediate products for producing isoxazolin-3-yl-acylbenzenenes
-
The present invention describes a process for preparing isoxazoles of the formula I where: R1is hydrogen, C1-C6-alkyl, R2is hydrogen, C1-C6-alkyl, R3, R4, R5are each hydrogen, C1-C6-alkyl or R4and R5together from a bond, R6is a heterocysclic ring, n is 0, 1 or 2; which comprises preparing an intermediate of the formula VI where R1, R3, R4and R5are each as defined above, followed by halogenation, thiomethylation, oxidation and acylation to give compounds of the formula I. Furthermore, the invention describes novel intermediates for preparing the compounds of the formula I and novel processes for preparing the intermediates.
- -
-
-
- o-Nitroaryldioxolane for protection of pheromones. Study of the photodelivery of carbonylic compounds
-
o-Nitrophenyldioxolanes 1 to 12 have been prepared and the rate of their photocleavage determined Steric congestion in the molecule causes a decrease of the reaction rate. The decrease in the rate is especially important in the presence of a nitro group in a second phenyl ring.
- Ceita, Luisa,Maiti, Amiya K.,Mestres, Ramon,Tortajada, Amparo
-
p. 1023 - 1055
(2007/10/03)
-
- Polyaza heterocycles. Part 3. Halogenation of 1-substituted quinoxalinocinnolines: mechanistic implications
-
Since it has been proposed that halogenation of quinoxalinocinnolines at C-10, using hydrogen chloride or bromide in chloroform, occurs through initial protonation of the substrate at N-12, attempts have been made to inhibit this protonation by the introduction of an additional substituent at C-1.Where this substituent is chloro, bromo or methyl, chlorination still occurs preferentially at C-10, although the yield and the reaction rate decrease along the series, lending weight to the mechanistic proposal.
- Harvey, Ian W.,Smith, David M.,White, Charles R.
-
p. 1699 - 1704
(2007/10/03)
-