2040-26-8Relevant academic research and scientific papers
Reaction of selenoketones with propiolic acid
Okuma, Kentaro,Koda, Masahiro,Shigetomi, Toshiyuki
, p. 1057 - 1060 (2008)
The reaction of di-tert-butyl selenoketone with propiolic acid gave 2H,6H-1,3-oxaselenin-6-one in 78% yield, whereas the reaction of di-tert-butyl thioketone with propiolic acid recovered starting thioketone almost quantitatively. On the other hand, the r
Synthesis of sterically hindered ketones from aldehydes via O-silyl oximes
Kim, Joong-Gon,Mishra, Mithilesh Kumar,Jang, Doo Ok
, p. 3527 - 3529 (2012)
A mild and efficient method to synthesize sterically hindered ketones from aldehydes via O-silyl oximes was developed. Treatment of O-triphenylsilylated oximes with alkyl iodides in the presence of triethyl borane afforded the corresponding ketones.
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.
1,3-Alkyl Transposition in Allylic Alcohols Enabled by Proton-Coupled Electron Transfer
Knowles, Robert R.,Seidler, Gesa,Zhao, Kuo
supporting information, p. 20190 - 20195 (2021/08/13)
A method is described for the isomerization of acyclic allylic alcohols into β-functionalized ketones via 1,3-alkyl transposition. This reaction proceeds via light-driven proton-coupled electron transfer (PCET) activation of the O?H bond in the allylic al
Light-DrivenN-Heterocyclic Carbene Catalysis Using Alkylborates
Sato, Yukiya,Goto, Yamato,Nakamura, Kei,Miyamoto, Yusuke,Sumida, Yuto,Ohmiya, Hirohisa
, p. 12886 - 12892 (2021/10/29)
Radical-radical coupling, the selective reaction between two different radical species, has contributed to the methodology for connecting bulky units. Light-drivenN-heterocyclic carbene (NHC) organocatalysis is recognized as a state-of-the-art methodology enabling radical-radical coupling. The catalytic process involves forming an acyl azolium intermediate from the NHC catalyst and an acyl donor, followed by single electron reduction of this key intermediate, which is largely dependent on the photoredox catalyst. We designed a radical NHC catalysis in which the direct photoexcitation of a borate to form a high reducing agent facilitated the single electron reduction event. The borate produces an alkyl radical for the single electron transfer process to accomplish the radical-radical coupling. This protocol enables cross-coupling between alkylborates and acyl imidazoles in addition to radical relay-type alkylacylations of alkenes with alkylborates and acyl imidazoles, affording ketones with a broad scope.
Photochemical oxidation of benzylic primary and secondary alcohols utilizing air as the oxidant
Nikitas, Nikolaos F.,Tzaras, Dimitrios Ioannis,Triandafillidi, Ierasia,Kokotos, Christoforos G.
, p. 471 - 477 (2020/02/13)
A mild and green photochemical protocol for the oxidation of alcohols to aldehydes and ketones was developed. Utilizing thioxanthenone as the photocatalyst, molecular oxygen from air as the oxidant and cheap household lamps or sunlight as the light source, a variety of primary and secondary alcohols were converted into the corresponding aldehydes or ketones in low to excellent yields. The reaction mechanism was extensively studied.
Electrochemical [4+2] Annulation-Rearrangement-Aromatization of Styrenes: Synthesis of Naphthalene Derivatives
Ma, Yueyue,Lv, Jufeng,Liu, Chengyu,Yao, Xiantong,Yan, Guoming,Yu, Wei,Ye, Jinxing
supporting information, p. 6756 - 6760 (2019/04/17)
We report the first electrochemical strategy to synthesize functionalized naphthalene derivatives through [4+2] annulation—rearrangement–aromatization from styrenes under mild conditions. The electrolysis does not require metals, oxidants and high valence substrates, indicating the atom and step-economy ideals. The dehydrodimer produced through [4+2] cycloaddition of 4-methoxy α-methyl styrene is isolated and proved to be the key intermediate for the following oxydehydrogenation to form carbon cation, which undergoes rearrangement–aromatization to afford the final products. This reaction represents a powerful access to construct multi-substituted naphthalene blocks in a single step.
Phosphazene Base tBu-P4 Catalyzed Methoxy–Alkoxy Exchange Reaction on (Hetero)Arenes
Shigeno, Masanori,Hayashi, Kazutoshi,Nozawa-Kumada, Kanako,Kondo, Yoshinori
supporting information, p. 6077 - 6081 (2019/03/26)
The organic superbase tBu-P4 catalyzes methoxy-alkoxy exchange reactions on (hetero)arenes with alcohols. The catalytic reaction proceeded efficiently with electron-deficient methoxy(hetero)arenes as well as with a variety of alcohols, including 3-amino-1-propanol, β-citronellol, menthol, and cholesterol. An intramolecular version of this reaction furnished six- and seven-membered ring compounds.
N-Heterocyclic Carbene-Catalyzed Decarboxylative Alkylation of Aldehydes
Ishii, Takuya,Kakeno, Yuki,Nagao, Kazunori,Ohmiya, Hirohisa
supporting information, p. 3854 - 3858 (2019/04/25)
We found that N-heterocyclic carbene catalysis promoted the unprecedented decarboxylative coupling of aryl aldehydes and tertiary or secondary alkyl carboxylic acid-derived redox-active esters to produce aryl alkyl ketones. The mild and transition-metal-free reaction conditions are attractive features of this method. The power of this protocol was demonstrated by the functionalization of pharmaceutical drugs and natural product. A reaction pathway involving single electron transfer from an enolate form of Breslow intermediate to a redox ester followed by recombination of the resultant radical pair to form a carbon-carbon bond is proposed.
Cp?Co(III)-Catalyzed C-H Alkylation with Maleimides Using Weakly Coordinating Carbonyl Directing Groups
Mandal, Rajib,Emayavaramban, Balakumar,Sundararaju, Basker
supporting information, p. 2835 - 2838 (2018/05/29)
A novel protocol for ortho-C-H alkylation of aromatic and heteroaromatic ketones and esters under Cp?Co(III) catalysis has been developed for the first time. The reaction proceeds through initial cyclometalation via weak chelation-assisted C-H bond activation, followed by coordination of activated alkene, insertion between Co-C, and protodemetalation.
