1020957-75-8Relevant academic research and scientific papers
Catalyst-free photodecarbonylation ofortho-amino benzaldehyde
Li, Lamei,Wang, Songping,Wei, Wentao,Yan, Ming,Zhou, Jingwei
supporting information, p. 3421 - 3426 (2020/06/25)
It is almost a consensus that decarbonylation of the aldehyde group (-CHO) needs to not only be mediated by transition metal catalysts, but also requires severe reaction conditions (high temperature and long reaction time). In this work, inspired by the “conformational-selectivity-based” design strategy, we broke this consensus and discovered a catalyst-free photodecarbonylation of the aldehyde group. It revealed that decarbonylation can be easily achieved with visible light irradiation by introducing a tertiary amine into theortho-position of the aldehyde group. A diverse array of tertiary amines is tolerated by our photodecarbonylation under mild conditions. Furthermore, the (QM) computations of the mechanism and the experiments on well-designed special substrates revealed that our photodecarbonylation depends on the conformational specificity of the aldehyde group and tertiary amine, and occurs through an unusual [1,4]-H shift and a subsequent [1,3]-H shift.
Expeditious Synthesis of Multisubstituted Quinolinone Derivatives Based on Ring Recombination Strategy
Yokoo, Kazuma,Mori, Keiji
supporting information, p. 244 - 248 (2019/12/30)
We achieved a concise construction of 3-substituted quinolinone derivatives based on a ring recombination strategy. In this process, seven transformations involving two types of cyclization proceeded in one pot to afford various quinolinone derivatives in good to excellent chemical yields (up to 98%).
Potassium tert-Butoxide-Mediated Condensation Cascade Reaction: Transition Metal-Free Synthesis of Multisubstituted Aryl Indoles and Benzofurans
Yang, Pengfei,Xu, Weiyan,Wang, Rongchao,Zhang, Min,Xie, Chunsong,Zeng, Xiaofei,Wang, Min
supporting information, p. 3658 - 3662 (2019/05/17)
An efficient and facile method to synthesize valuable disubstituted 2-aryl indoles and benzofurans in good yields has been demonstrated, based on a tert-butoxide-mediated condensation reaction involving a vinyl sulfoxide intermediate. Products are obtained from N- or O-benzyl benzaldehydes using dimethyl sulfoxide as a carbon source. The methodology features a wide functional group tolerance and transition metal-free environment. Preliminary mechanistic studies suggest that the reaction involves a tandem aldol reaction/Michael addition/dehydrosulfenylation/isomerization sequence through an ionic protocol.
Spirocyclic Tetramates by Sequential Knoevenagel and [1,5]-Prototropic Shift
Josa-Culleré, Laia,Hirst, Michael G.,Lockett, Jonathan P.,Thompson, Amber L.,Moloney, Mark G.
, p. 9671 - 9683 (2019/09/06)
Highly functionalized spirocyclic tetramates were prepared via a sequential Knoevenagel reaction and [1,5]-prototropic shift (T-reaction) of bicyclic tetramates. While these compounds isomerize in solution, stable analogues can be prepared via an appropri
Investigation of the [1,5]-hydride shift as a route to nitro-Mannich cyclisations
Anderson, James C.,Chang, Chia-Hao,Corpinot, Mérina K.,Nunn, Michael,Ware, Oliver J.
, (2019/10/14)
Conditions were found for the [1,5]-hydride shift nitro-Mannich reaction that led to the synthesis of 2,3-disubstituted tetrahydroquinolines. Two simple cyclic amine substrates gave diastereomerically pure rearranged products in 65 and 90% yields by refluxing in HFIP. A more general procedure used Gd(OTf)3 as a catalyst and successfully rearranged other cyclic and acyclic amines in 42–84% yield with diastereomeric ratios of 75:25 to >95:5 in favour of the anti-diastereoisomer (9 examples). Two examples of sulphur containing heterocycles gave lower yields of 9 and 25%. Electron withdrawing substituents were shown to have a deleterious effect on the success of the reaction. The results indicated the limitation of the [1,5]-hydride shift nitro-Mannich reaction with respect to the stability of the intermediate iminium ion.
Expedient synthesis of tetrahydroquinoline-3-spirohydantoin derivatives: Via the Lewis acid-catalyzed tert -amino effect reaction
Briones, John F.,Basarab, Gregory S.
supporting information, p. 8541 - 8544 (2016/07/13)
Magnesium triflate was found to effectively catalyze the tert-amino effect reaction (T-reaction) involving ethyl 3-(2-(dialkylamino)-phenyl)-2-nitroacrylates leading to tetrahydroquinoline nitroester derivatives. These compounds can be readily transformed
Asymmetric tandem 1,5-hydride shift/ring closure for the synthesis of chiral spirooxindole tetrahydroquinolines
Cao, Weidi,Liu, Xiaohua,Guo, Jing,Lin, Lili,Feng, Xiaoming
supporting information, p. 1632 - 1636 (2015/01/30)
The direct functionalization of sp3 C-H bonds through a tandem 1,5-hydride shift/ring closure is described. Various optically active spirooxindole tetrahydroquinoline derivatives bearing contiguous quaternary or tertiary stereogenic carbon centers were readily synthesized. A chiral scandium complex of N,N'-dioxide promoted the reactions in good yields (up to 97%) with excellent diastereoselectivities (>20:1) and enantioselectivities (up to 94% ee). Kinetic isotope effect (KIE) experiments and internal redox reactions of chiral substrates were conducted, and the results provided intriguing information that helped clarify the mechanism of the reaction.
PhI(OAc)2-mediated intramolecular oxidative aryl-aldehyde C sp 2-C sp 2 bond formation: Metal-free synthesis of acridone derivatives
Zheng, Zisheng,Dian, Longyang,Yuan, Yucheng,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
, p. 7451 - 7458 (2014/09/17)
A metal-free protocol for direct aryl-aldehyde Csp2-Csp 2 bond formation via a PhI(OAc)2-mediated intramolecular cross-dehydrogenative coupling (CDC) of various 2-(N-arylamino)aldehydes was developed. The novel methodology requires no need of preactivation of the aldehyde group, is applicable to a large variety of functionalized substrates, and most of all provides a convenient approach to the construction of biologically important acridone derivatives.
2-aminobenzaldehydes as versatile substrates for rhodium-catalyzed alkyne hydroacylation: Application to dihydroquinolone synthesis
Castaing, Matthias,Wason, Sacha L.,Estepa, Beatriz,Hooper, Joel F.,Willis, Michael C.
supporting information, p. 13280 - 13283 (2014/01/06)
Amine for it! A cationic rhodium catalyst, which was assembled insitu from commercial components, promoted the reaction of a range of simple 2-aminobenzaldehydes with terminal and internal alkynes in a series of intermolecular hydroacylation reactions. The products of this reaction, amino-substituted enones, were efficiently converted into the corresponding dihydro-4-quinolones.
Visible light photooxidative cyclization of amino alcohols to 1,3-oxazines
Mathis, Cheryl L.,Gist, Brandi M.,Frederickson, Conerd K.,Midkiff, Katie M.,Marvin, Christopher C.
, p. 2101 - 2104 (2013/04/24)
1,3-Amino alcohols were prepared to examine how structure affects the oxidation of tertiary amines in visible light photocatalysis. These substrates were cyclized to produce oxazines following the photooxidative formation of iminium ions using catalytic Ru(bpy)3Cl2. Amino alcohol derivatives of tetrahydroisoquinoline, tetrahydroquinoline, pyrrolidine, and Δ3-piperidine all were found to be viable substrates. In the case of the unsaturated piperidines, cyclization is accompanied by addition of methanol across the alkene; most likely occurring via a conjugate addition to an intermediate α,β-unsaturated iminium ion prior to oxazine formation.
