15325-56-1Relevant academic research and scientific papers
Equilibration of 5-Methyl-3-hexen-2-one and 5-Methyl-3-hexen-2-one and of XCH2CH=CYZ/XCH=CHCHYZ Pairs in General
Hine, Jack,Linden, Shwn-Meei
, p. 584 - 587 (1983)
The equilibrium constant for isomerization of 5-methyl-4-hexen-2-one to trans-5-methyl-3-hexen-2-one in tert-butyl alcohol at 25 deg C has been found to be 0.40, which is smaller by 250-fold than a literature value.This and other equilibrium constants for reactions of the type XCH2CH=CMe2 XCH=CHCHME2 are shown to be consistent with the double bond stabilizing abilities of various groups as measured by equilibrium constants for reactions of the type XCH2CH=CHY XCH=CHCH2Y.The general case of isomerizations of the type XCH2CH=CYZ XCH=CHCHYZ is also discussed.
Visible-light-mediated alkylation of 4-alkyl-1,4-dihydropyridines with alkenyl sulfones
Dong, Jianyang,Liu, Yuxiu,Wang, Qingmin,Yue, Fuyang
supporting information, p. 8924 - 8928 (2021/11/04)
Herein we report a mild, general protocol for visible-light-mediated alkylation of 4-alkyl-1,4-dihydropyridines with alkenyl sulfones. The protocol permits efficient functionalization of sulfones with a broad range of cyclic and acyclic secondary and tert
Kinetic resolution ofN-aryl β-amino alcoholsviaasymmetric aminations of anilines
Guo, Zheng,Xie, Jinglei,Hu, Tao,Chen, Yunrong,Tao, Houchao,Yang, Xiaoyu
supporting information, p. 9394 - 9397 (2021/09/22)
An efficient kinetic resolution ofN-aryl β-amino alcohols has been developedviaasymmetricpara-aminations of anilines with azodicarboxylates enabled by chiral phosphoric acid catalysis. Broad substrate scope and high kinetic resolution performances were afforded with this method. Control experiments supported the critical roles of the NH and OH group in these reactions.
Catalytic Intermolecular C(sp3)-H Amination: Selective Functionalization of Tertiary C-H Bonds vs Activated Benzylic C-H Bonds
Brunard, Erwan,Boquet, Vincent,Van Elslande, Elsa,Saget, Tanguy,Dauban, Philippe
supporting information, p. 6407 - 6412 (2021/05/29)
A catalytic intermolecular amination of nonactivated tertiary C(sp3)-H bonds (BDE of 96 kcal·mol-1) is reported for substrates displaying an activated benzylic site (BDE of 85 kcal·mol-1). The tertiary C(sp3)-H bond is selectively functionalized to afford α,α,α-Trisubstituted amides in high yields. This unusual site-selectivity results from the synergistic combination of Rh2(S-Tfpttl)4, a rhodium(II) complex with a well-defined catalytic pocket, with tert-butylphenol sulfamate (TBPhsNH2), which leads to a discriminating rhodium-bound nitrene species under mild oxidative conditions. This catalytic system is very robust, and the reaction was performed on a 50 mmol scale with only 0.01 mol % of catalyst. The TBPhs group can be removed under mild conditions to afford the corresponding NH-free amines.
Enantio- and Regioselective NiH-Catalyzed Reductive Hydroarylation of Vinylarenes with Aryl Iodides
He, Yuli,Liu, Chuang,Yu, Lei,Zhu, Shaolin
supporting information, p. 21530 - 21534 (2020/10/02)
A highly enantio- and regioselective hydroarylation process of vinylarenes with aryl halides has been developed using a NiH catalyst and a new chiral bis imidazoline ligand. A broad range of structurally diverse, enantioenriched 1,1-diarylalkanes, a structure found in a number of biologically active molecules, have been obtained with excellent yields and enantioselectivities under extremely mild conditions.
Enzymatic Primary Amination of Benzylic and Allylic C(sp3)-H Bonds
Jia, Zhi-Jun,Gao, Shilong,Arnold, Frances H.
supporting information, p. 10279 - 10283 (2020/07/27)
Aliphatic primary amines are prevalent in natural products, pharmaceuticals, and functional materials. While a plethora of processes are reported for their synthesis, methods that directly install a free amine group into C(sp3)-H bonds remain unprecedented. Here, we report a set of new-to-nature enzymes that catalyze the direct primary amination of C(sp3)-H bonds with excellent chemo-, regio-, and enantioselectivity, using a readily available hydroxylamine derivative as the nitrogen source. Directed evolution of genetically encoded cytochrome P411 enzymes (P450s whose Cys axial ligand to the heme iron has been replaced with Ser) generated variants that selectively functionalize benzylic and allylic C-H bonds, affording a broad scope of enantioenriched primary amines. This biocatalytic process is efficient and selective (up to 3930 TTN and 96percent ee), and can be performed on preparative scale.
Nickel-Catalyzed Anionic Cross-Coupling Reaction of Lithium Sulfonimidoyl Alkylidene Carbenoids With Organolithiums
Bülow, Gerd,Baik, Mu-Hyun,Decker, Jürgen,Erdelmeier, Irene,Gais, Hans-Joachim,Park, Steve,Won, Joonghee
supporting information, (2020/02/28)
The mechanistic platform for a novel nickel0-catalyzed anionic cross-coupling reaction (ACCR) of lithium sulfonimidoyl alkylidene carbenoids (metalloalkenyl sulfoximines) with organometallic reagents is reported herein, affording substituted alkenylmetals and lithium sulfinamides. The Ni0-catalyzed ACCR of three different types of metalloalkenyl sulfoximines, including acyclic, axially chiral and exocyclic derivatives, with sp2 organolithiums and sp2 and sp3 Grignard reagents has been studied. The ACCR of metalloalkenyl sulfoximines with PhLi in the presence of the Ni0-catalyst and precatalyst Ni(PPh3)2Cl2 afforded alkenyllithiums, under inversion of configuration at the C atom and complete retention at the S atom. In a combination of experimental and DFT studies, we propose a catalytic cycle of the Ni0-catalyzed ACCR of lithioalkenyl sulfoximines. Computational studies reveal two distinctive pathways of the ACCR, depending on whether a phosphine or 1,5-cyclooctadiene (COD) is the ligand of the Ni atom. They rectify the underlying importance of forming the key Ni0-vinylidene intermediate through an indispensable electron-rich Ni0-center coordinated by phosphine ligands. Fundamentally, we present a mechanistic study in controlling the diastereoselectivity of the alkenyllithium formation via the key lithium sulfinamide coordinated Ni0-vinylidene complex, which consequently avoids an unselective formation of an alkylidene carbene Ni-complex and ultimately racemic alkenyllithium.
Iron-Catalyzed Cross-Coupling of Alkynyl and Styrenyl Chlorides with Alkyl Grignard Reagents in Batch and Flow
Deng, Yuchao,Wei, Xiao-Jing,Wang, Xiao,Sun, Yuhan,No?l, Timothy
, p. 14532 - 14535 (2019/11/21)
Transition-metal-catalyzed cross-coupling chemistry can be regarded as one of the most powerful protocols to construct carbon–carbon bonds. While the field is still dominated by palladium catalysis, there is an increasing interest to develop protocols that utilize cheaper and more sustainable metal sources. Herein, we report a selective, practical, and fast iron-based cross-coupling reaction that enables the formation of Csp?Csp3 and Csp2?Csp3 bonds. In a telescoped flow process, the reaction can be combined with the Grignard reagent synthesis. Moreover, flow allows the use of a supporting ligand to be avoided without eroding the reaction selectivity.
RETRACTED ARTICLE: Copper-Catalyzed Decarboxylative C(sp2)-C(sp3) and C(sp)-C(sp3) Coupling of Substituted Cinnamic Acids and 3-Phenyl Propiolic Acid with N-Tosyl Oxaziridines
Nguyen, Bich-Ngoc,Cao, Hai-Thuong
supporting information, p. 5912 - 5915 (2019/08/07)
A mild and efficient strategy for decarboxylative C(sp2)-C(sp3) and C(sp)-C(sp3) coupling of α,β-unsaturated carboxylic acids such as substituted cinnamic acids and 3-phenyl propiolic acid with N-Tosyl oxaziridines was developed. The corresponding products were achieved in moderate to good yields with excellent stereoselectivity. Base-free and oxidant-free conditions allow good functional group tolerance. Radical inhibitors such as TEMPO and BHT completely suppressed the reactions suggesting a radical mechanism was involved. This study is supposed to broaden the frontier of oxaziridines' chemistry and to open up a novel cascade for alkylating reagents.
Controllable Isomerization of Alkenes by Dual Visible-Light-Cobalt Catalysis
Meng, Qing-Yuan,Schirmer, Tobias E.,Katou, Kousuke,K?nig, Burkhard
supporting information, p. 5723 - 5728 (2019/04/03)
We report herein that thermodynamic and kinetic isomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor–acceptor dye 4CzIPN accelerates the reaction further. Transformation of exocyclic alkenes into the corresponding endocyclic products could be efficiently realized by using 4CzIPN and Co(acac)2 in the absence of any additional ligands. Spectroscopic and spectroelectrochemical investigations indicate CoI being involved in the generation of a Co hydride, which subsequently adds to alkenes initiating the isomerization.
