6992-97-8Relevant academic research and scientific papers
Copper-catalyzed arene amination in pure aqueous ammonia
Takagi, Mio,Watanabe, Ayako,Murata, Shigeo,Takita, Ryo
supporting information, p. 1791 - 1795 (2019/02/20)
A simple protocol for copper-catalyzed arene amination using aqueous ammonia without any additional ligands and organic coordinating solvents has been developed. The reaction pathway via a Cu(i)/Cu(iii) mechanism is proposed based on the results of control experiments as well as DFT calculations.
Hypervalent Iodine(III)-Catalyzed Balz–Schiemann Fluorination under Mild Conditions
Xing, Bo,Ni, Chuanfa,Hu, Jinbo
supporting information, p. 9896 - 9900 (2018/07/31)
An unprecedented hypervalent iodine(III) catalyzed Balz–Schiemann reaction is described. In the presence of a hypervalent iodine compound, the fluorination reaction proceeds under mild conditions (25–60 °C), and features a wide substrate scope and good functional-group compatibility.
One-pot Construction of Difluorinated Pyrrolizidine and Indolizidine Scaffolds via Copper-Catalyzed Radical Cascade Annulation
Wang, Xiaoyang,Li, Miao,Yang, Yanyan,Guo, Minjie,Tang, Xiangyang,Wang, Guangwei
supporting information, p. 2151 - 2156 (2018/04/26)
A convenient approach to the synthesis of diverse difluorinated nitrogen-containing polycycles via a copper-catalyzed radical cascade annulation of amine-containing olefins and ethyl bromodifluoroacetate was developed. Three new bonds, including a Csp3 ?CF2 and two C?N bonds, are forged simultaneously in this strategy. Through this strategy, a series of difluorinated pyrrolizidine and indolizidine derivatives have been conveniently synthesized in good yields. (Figure presented.).
Catalytic, Enantioselective, Intramolecular Sulfenoamination of Alkenes with Anilines
Denmark, Scott E.,Chi, Hyung Min
, p. 3826 - 3843 (2017/04/13)
A method for the catalytic, enantioselective, intramolecular sulfenoamination of alkenes with aniline nucleophiles has been developed. The method employs a chiral, Lewis basic selenophosphoramide catalyst and a Br?nsted acid co-catalyst to promote stereocontrolled C-N and C-S bond formation by activation of an achiral sulfenylating agent. Benzoannulated nitrogen-containing heterocycles such as indolines, tetrahydroquinolines, and tetrahydrobenzazepines were prepared with high to excellent enantioselectivities. The impact of tether length and electron density of both the nucleophile and olefin on the reactivity, site selectivity, and enantioselectivity were investigated and interpreted in terms of substrate-dependent stereodetermining thiiranium ion formation or capture.
Pd-Catalyzed Intramolecular Aminoalkylation of Unactivated Alkenes: Access to Diverse N-Heterocycles
Ye, Liu,Lo, Kai-Yip,Gu, Qiangshuai,Yang, Dan
supporting information, p. 308 - 311 (2017/04/21)
A highly efficient palladium-catalyzed intramolecular aminoalkylation of unactivated alkenes in the absence of an external ligand and oxidant is described. New C-N and C(sp3)-C(sp3) bonds are formed simultaneously. This general transformation allows for construction of diverse N-heterocycles. Mechanistic studies show that the process may involve a four-membered Pd(alkyl)amido intermediate.
Assembly of Primary (Hetero)Arylamines via CuI/Oxalic Diamide-Catalyzed Coupling of Aryl Chlorides and Ammonia
Fan, Mengyang,Zhou, Wei,Jiang, Yongwen,Ma, Dawei
supporting information, p. 5934 - 5937 (2015/12/11)
A general and practical catalytic system for aryl amination of aryl chlorides with aqueous or gaseous ammonia has been developed, with CuI as the catalyst and bisaryl oxalic diamides as the ligands. The reaction proceeds at 105-120°C to provide a diverse set of primary (hetero)aryl amines in high yields with various functional groups.
Palladium-catalyzed amination of aryl chlorides and bromides with ammonium salts
Green, Rebecca A.,Hartwig, John F.
supporting information, p. 4388 - 4391 (2015/01/08)
We report the palladium-catalyzed coupling of aryl halides with ammonia and gaseous amines as their ammonium salts. The coupling of aryl chlorides and ortho-substituted aryl bromides with ammonium sulfate forms anilines with higher selectivity for the primary arylamine over the diarylamine than couplings with ammonia in dioxane. The resting state for the reactions of aryl chlorides is different from the resting state for the reactions of aryl bromides, and this change in resting states is proposed to account for a difference in selectivities for reactions of the two haloarenes.
Tailoring atropisomeric maleimides for stereospecific [2 + 2] photocycloaddition-photochemical and photophysical investigations leading to visible-light photocatalysis
Kumarasamy, Elango,Raghunathan, Ramya,Jockusch, Steffen,Ugrinov, Angel,Sivaguru
, p. 8729 - 8737 (2014/07/07)
Atropisomeric maleimides were synthesized and employed for stereospecific [2 + 2] photocycloaddition. Efficient reaction was observed under direct irradiation, triplet-sensitized UV irradiation, and non-metal catalyzed visible-light irradiation, leading to two regioisomeric (exo/endo) photoproducts with complete chemoselectivity (exclusive [2 + 2] photoproduct). High enantioselectivity (ee > 98%) and diastereoselectivity (dr > 99:1%) were observed under the employed reaction conditions and were largely dependent on the substituent on the maleimide double bond but minimally affected by the substituents on the alkenyl tether. On the basis of detailed photophysical studies, the triplet energies of the maleimides were estimated. The triplet lifetimes appeared to be relatively short at room temperature as a result of fast [2 + 2] photocycloaddition. For the visible-light mediated reaction, triplet energy transfer occurred with a rate constant close to the diffusion-limited value. The mechanism was established by generation of singlet oxygen from the excited maleimides. The high selectivity in the photoproduct upon reaction from the triplet excited state was rationalized on the basis of conformational factors as well as the type of diradical intermediate that was preferred during the photoreaction.
Intramolecular aminocyanation of alkenes by cooperative palladium/boron catalysis
Miyazaki, Yosuke,Ohta, Naoki,Semba, Kazuhiko,Nakao, Yoshiaki
supporting information, p. 3732 - 3735 (2014/04/03)
A cooperative palladium/triorganoboron catalyst to accomplish the intramolecular aminocyanation of alkenes through the cleavage of N-CN bonds is reported. 4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene (Xantphos) is found to be crucial as a ligand for palladium to effectively catalyze the transformation with high chemo- and regioselectivity. A range of substituted indolines and pyrrolidines with both tetra- or trisubstituted carbon and cyano functionalities are readily furnished by the newly developed cyanofunctionalization reaction. A preliminary example of enantioselective aminocyanation is also described.
Organocatalytic approach to benzofused nitrogen-containing heterocycles: Enantioselective total synthesis of (+)-angustureine
Fustero, Santos,Moscardo, Javier,Jimenez, Diego,Perez-Carrion, Maria Dolores,Sanchez-Rosello, Maria,Del Pozo, Carlos
supporting information; experimental part, p. 9868 - 9872 (2009/10/20)
A study was conducted to demonstrate an organocatalytic approach to benzofused nitrogen-containing heterocycles. he study also demonstrated enantioselective total synthesis of (+)-angustureine. It reported the easy an d enantioselective preparation of tet
