134-84-9Relevant articles and documents
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Denney et al.
, p. 46,50 (1964)
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Brown,Jensen
, p. 2296,2297 (1958)
The Most Twisted Acyclic Amides: Structures and Reactivity
Liu, Chengwei,Shi, Shicheng,Liu, Yongmei,Liu, Ruzhang,Lalancette, Roger,Szostak, Roman,Szostak, Michal
, p. 7771 - 7774 (2018)
The synthesis, crystal structures, and reactivity of the most twisted acyclic amides described to date are reported. Substitution at the nitrogen atom in simple benzamides with Ts and acyl or carbamate groups provides a unique way to achieve almost perpendicular twist in N-acyclic amides (= 77°, N = Ac; = 87°, N = Boc). The overlap between the Nlp and CO π? orbital is disrupted due to geometrical constraints around the N-substituents. The perpendicular acyclic twisted amides represent a transition state mimic of cis-trans peptide isomerization thus far only accessible by excessively twisted bridged lactams.
A Simple and Effective Method for Catalytic Oxidation of Alcohols Using the Oxone/Bu4NHSO4 Oxidation System
An, X. Q.,Kang, M.,Ma, H. C.,Yang, Y. X.,Yang, Z. W.,Zeng, W.
, p. 521 - 523 (2020)
Abstract: A simple and efficient procedure is reported for the oxidation of alcohols tocarbonyl compounds with Oxone (potassium peroxymonosulfate) in the presence oftetrabutylammonium hydrogen sulfate as catalyst with excellent conversion andhigh selectivity using chloroform as solvent at room temperature. The efficiencyof several phase-transfer catalysts in the oxidation of benzyl alcohols andbenzydrol was studied. The proposed catalytic system was also evaluated in theoxidation of alcohols in water at room temperature.
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White et al.
, p. 3613 (1961)
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Brown,Marino
, p. 3308 (1959)
Direct Formation and Subsequent Substitution of Remote Ketone-Functionalized Organocopper Reagents
Ebert, Greg W.,Klein, Walter R.
, p. 4744 - 4747 (1991)
Remote ketone-functionalized aryl- and alkylcopper reagents have been synthesized by the use of a highly activated form of zero-valent copper. 5-Bromo-2-pentanone and 4-iodobenzophenone undergo oxidative addition with activated copper to form 5-cuprio-2-pentanone and 4-cupriobenzophenone, respectively.These, in turn, can be cross-coupled with alkyl halides to produce the corresponding alkylated ketones and with acid chlorides to form the corresponding diketones.By use of this methodology, a two-step, one-pot synthesis of methyl (E)-9-oxo-2-decenoate and 8-nonen-2-one have been achieved.The former compound is the methyl ester of the "queen substance" of the honey bee, and the latter is part of an "attractant mixture" for cheese mites found in cheddar cheese.These syntheses were accomplished by converting commercially available 6-bromo-2-hexanone to 6-cuprio-2-hexanone followed by cross-coupling with commercially available methyl 4-bromocrotonate and allyl bromide, respectively.
IPr# - highly hindered, broadly applicable N-heterocyclic carbenes
Flach, Carol,Lalancette, Roger,Li, Guangchen,Mendelsohn, Richard,Meng, Guangrong,Szostak, Michal,Szostak, Roman,Zhao, Qun
, p. 10583 - 10589 (2021)
IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) represents the most important NHC (NHC = N-heterocyclic carbene) ligand throughout the field of homogeneous catalysis. Herein, we report the synthesis, catalytic activity, and full structural and electronic characterization of novel, sterically-bulky, easily-accessible NHC ligands based on the hash peralkylation concept, including IPr#, Np# and BIAN-IPr#. The new ligands have been commercialized in collaboration with Millipore Sigma: IPr#HCl, 915653; Np#HCl; 915912; BIAN-IPr#HCl, 916420, enabling broad access of the academic and industrial researchers to new ligands for reaction optimization and screening. In particular, the synthesis of IPr# hinges upon cost-effective, modular alkylation of aniline, an industrial chemical that is available in bulk. The generality of this approach in ligand design is demonstrated through facile synthesis of BIAN-IPr# and Np#, two ligands that differ in steric properties and N-wingtip arrangement. The broad activity in various cross-coupling reactions in an array of N-C, O-C, C-Cl, C-Br, C-S and C-H bond cross-couplings is demonstrated. The evaluation of steric, electron-donating and π-accepting properties as well as coordination chemistry to Au(i), Rh(i) and Pd(ii) is presented. Given the tremendous importance of NHC ligands in homogenous catalysis, we expect that this new class of NHCs will find rapid and widespread application.
Palladium-NHC (NHC = N-heterocyclic Carbene)-Catalyzed Suzuki-Miyaura Cross-Coupling of Alkyl Amides
Wang, Chang-An,Rahman, Md. Mahbubur,Bisz, Elwira,Dziuk, B?az?ej,Szostak, Roman,Szostak, Michal
, p. 2426 - 2433 (2022/02/17)
We report the Pd-catalyzed Suzuki-Miyaura cross-coupling of aliphatic amides. Although tremendous advances have been made in the cross-coupling of aromatic amides, C-C bond formation from aliphatic amides by selective N-C(O) cleavage has remained a major challenge. This longstanding problem in Pd catalysis has been addressed herein by a combination of (1) the discovery of N,N-pym/Boc amides as a class of readily accessible amide-based reagents for cross-coupling and (2) steric tuning of well-defined Pd(II)-NHC catalysts for cross-coupling. The methodology is effective for the cross-coupling of an array of 3°, 2°, and 1° aliphatic amide derivatives. The catalyst system is user-friendly, since the catalysts are readily available and are air- and bench-stable. Mechanistic studies strongly support an amide bond twist and external nN → π*C═O/Ar delocalization as a unified enabling feature of N,N-pym/Boc amides in selective N-C(O) bond activation. The method provides a rare example of Pd-NHC-catalyzed cross-coupling of aliphatic acyl amide electrophiles.
Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen
Yu, Tao,Guo, Mingqing,Wen, Simiaomiao,Zhao, Rongrong,Wang, Jinlong,Sun, Yanli,Liu, Qixing,Zhou, Haifeng
, p. 13848 - 13852 (2021/04/22)
A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2as the sole oxidant with poly(ethylene glycol) dimethyl ether as a benign solvent has been developed. A wide range of monosubstituted,gem-disubstituted, 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins was successfully converted into the corresponding aldehydes and ketones in excellent yields even with gram-scale reaction. Some control experiments were also conducted to support a possible reaction pathway.