91639-72-4Relevant academic research and scientific papers
A Photosensitizer-Free Radical Cascade for Synthesizing CF3-Containing Polycyclic Quinazolinones with Visible Light
Hu, Qiang,Yu, Wan-Lei,Luo, Yong-Chun,Hu, Xiu-Qin,Xu, Peng-Fei
, p. 1493 - 1501 (2022/02/07)
Herein, we report an efficient photoinduced radical tandem trifluoromethylation/cyclization reaction of N-cyanamide alkenes for the synthesis of functionalized quinazolinones. Importantly, the reaction is carried out under mild conditions without any addi
Fluorocyclisation via I(I)/I(III) catalysis: A concise route to fluorinated oxazolines
Daniliuc, Constantin G.,Gilmour, Ryan,Kehr, Gerald,Meyer, Stephanie,Scheidt, Felix,Thiehoff, Christian,Yilmaz, Gülay
supporting information, p. 1021 - 1027 (2020/05/06)
Herein, we describe a catalytic fluorooxygenation of readily accessible N-allylcarboxamides via an I(I)/I(III) manifold to generate 2-oxazolines containing a fluoromethyl group. Catalysis is conditional on the oxidation competence of Selectfluor, whilst HF serves as both a fluoride source and Br?nsted acid activator. The C(sp3)–F bond of the mono-fluoromethyl unit and the C(sp3)–O bond of the ring are aligned in a synclinal relationship thereby engaging in stabilising hyperconjugative interactions with vicinal, electron-rich σ-bonds (σC–C→σ*C–F and σC–H→σ*C–O). This manifestation of the stereoelectronic gauche effect was established by X-ray crystallographic analysis of a representative example. Given the importance of fluorine in drug discovery, its ability to modulate conformation, and the prevalence of the 2-oxazoline scaffold in Nature, this strategy provides a rapid entry into an important bioisostere class.
Visible Light and Hydroxynaphthylbenzimidazoline Promoted Transition-Metal-Catalyst-Free Desulfonylation of N-Sulfonylamides and N-Sulfonylamines
Hasegawa, Eietsu,Nagakura, Yuto,Izumiya, Norihiro,Matsumoto, Keisuke,Tanaka, Tsukasa,Miura, Tomoaki,Ikoma, Tadaaki,Iwamoto, Hajime,Wakamatsu, Kan
supporting information, p. 10813 - 10825 (2018/07/30)
A visible light promoted process for desulfonylation of N-sulfonylamides and -amines has been developed, in which 1,3-dimethyl-2-hydroxynaphthylbenzimidazoline (HONap-BIH) serves as a light absorbing, electron and hydrogen atom donor, and a household white light-emitting diode serves as a light source. The process transforms various N-sulfonylamide and -amine substrates to desulfonylated products in moderate to excellent yields. The observation that the fluorescence of 1-methyl-2-naphthoxy anion is efficiently quenched by the substrates suggests that the mechanism for the photoinduced desulfonylation reaction begins with photoexcitation of the naphthoxide chromophore in HONap-BIH, which generates an excited species via intramolecular proton transfer between the HONap and BIH moieties. This process triggers single electron transfer to the substrate, which promotes loss of the sulfonyl group to form the free amide or amine. The results of studies employing radical probe substrates as well as DFT calculations suggest that selective nitrogen-sulfur bond cleavage of the substrate radical anion generates either a pair of an amide or amine anion and a sulfonyl radical or that of an amidyl or aminyl radical and sulfinate anion, depending on the nature of the N-substituent on the substrate. An intermolecular version of this protocol, in which 1-methyl-2-naphthol and 1,3-dimethyl-2-phenylbenzimidazoline are used concomitantly, was also examined.
Copper-Catalyzed Divergent Trifluoromethylation/Cyclization of Unactivated Alkenes
Zheng, Jing,Deng, Ziyang,Zhang, Yan,Cui, Sunliang
supporting information, p. 746 - 751 (2016/03/09)
Most of the precedent copper-catalyzed trifluoromethylation reactions of unactivated alkenes concern terminal alkenes, and these processes are terminated in elimination, or nucleophilic addition, or semipinacol rearrangement, or C-H bond functionalization steps. In this study, we develop a trifluoromethylation method for both unactivated terminal and internal alkenes to enable divergent late-stage radical cyclization and achieve high molecular complexity. These cyclizations are well consistent with Baldwin's rule. Furthermore, a kinetic isotope effect (KIE) study and control reactions were conducted, and a plausible mechanism is proposed.
Selective formation of secondary amides via the copper-catalyzed cross-coupling of alkylboronic acids with primary amides
Rossi, Steven A.,Shimkin, Kirk W.,Xu, Qun,Mori-Quiroz, Luis M.,Watson, Donald A.
supporting information, p. 2314 - 2317 (2013/06/05)
For the first time, a general catalytic procedure for the cross-coupling of primary amides and alkylboronic acids is demonstrated. The key to the success of this reaction was the identification of a mild base (NaOSiMe3) and oxidant (di-tert-butyl peroxide) to promote the copper-catalyzed reaction in high yield. This transformation provides a facile, high-yielding method for the monoalkylation of amides.
5-Exo versus 6-Endo cyclization of primary aminyl radicals: An experimental and theoretical investigation
Liu, Feng,Liu, Kun,Yuan, Xinting,Li, Chaozhong
, p. 10231 - 10234 (2008/09/17)
(Chemical Equation Presented) The cyclization of neutral primary pent-4-enylaminyl radicals was investigated experimentally and theoretically. Unlike the corresponding secondary aminyl radicals, primary pent-4-enylaminyl radicals underwent efficient cyclization to afford the pyrrolidine and/or piperidine products in good to high yields. While the simple pent-4-enylaminyl radical gave predominately the 5-exo cyclization product, 4-chloropent-4- enylaminyl radicals led to the formation of the corresponding 6-endo cyclization products in excellent regioselectivity. Theoretical calculations revealed that the 5-exo cyclization rate of primary aminyl radicals is about 3-4 orders of magnitude higher than that of secondary aminyl radicals.
Studies on the intramolecular cycloaddition reaction of isomunchnones derived from N-alkenyl substituted diazoimides
Padwa,Austin,Price,Weingarten
, p. 3247 - 3260 (2007/10/03)
A series of N-alkenyl substituted diazoimides were prepared and subjected to Rh(II) catalyzed decomposition. The initially generated rhodium carbenoid undergoes ready cyclization onto the neighboring amide carbonyl oxygen atom to generate an isomunchnone
Chemistry of Amidyl Radicals Produced from N-Hydroxypyridine-2-thione Imidate Esters
Esker, John L.,Newcomb, Martin
, p. 4933 - 4940 (2007/10/02)
The title radicals precursors were prepared from secondary amides by reaction of the amide with phosgene to give an imidoyl chloride followed by reaction with the sodium salt of N-hydroxypyridine-2-thione.Visible light initiated reactions of these precursors gave amidyl radicals 2 which could react with their precursors to give N-(2-pyridylthio) amides or with t-BuSH to give the parent amide.Radicals 2 containing δ,ε-unsaturation on the acyl or alkyl chain cyclized in a 5-exo fashion to give ultimately γ-lactams and N-acylpyrrolidines, respectively.Tandem 5-exo cyclizations of the N-allyl-4-pentenamidyl radical gave pyrrolizidinone products, and a tandem 5-exo/6-endo reaction sequence of the N-(4-pentenyl)benzamidyl radical gave, ultimately, 3,4-benzoindolizidinone.Several relative rate constants for cyclization and trapping of the amidyl radicals and for intramolecular reactions and trapping of the carbon-centered radicals formed by amidyl radical cyclizations were determined, and these values can be employed in synthetic planning.
FACILE PRODUCTION AND CYCLIZATIONS OF AMIDYL RADICALS
Newcomb, Martin,Esker, John L.
, p. 1035 - 1038 (2007/10/02)
Amides were converted via imidoyl chlorides into N-hydroxypyridine-2-thione imidate esters that were precursors for amidyl radicals; amidyl radicals containing δ,ε-unsaturation cyclized in a 5-exo fashion.
