2360-45-4Relevant articles and documents
Direct Synthesis of Chiral NH Lactams via Ru-Catalyzed Asymmetric Reductive Amination/Cyclization Cascade of Keto Acids/Esters
Shi, Yongjie,Tan, Xuefeng,Gao, Shuang,Zhang, Yao,Wang, Jingxin,Zhang, Xumu,Yin, Qin
supporting information, p. 2707 - 2713 (2020/03/30)
Lactams with a stereogenic center adjacent to the N atom have existed in many medicinal agents and bioactive alkaloids. Herein we report a broadly applicable synthesis of enantioenriched NH lactams through a one-pot asymmetric reductive amination/cyclization sequence of easily available keto acids/esters. Such cascade processes alleviate the demand for protecting group manipulations as well as intermediate purification. This strategy is capable of constructing enantioenriched lactams and benzo-lactams of a five-, six-, or seven-membered ring in generally high yield and with excellent enantioselectivities (up to 97% ee). Scalable and concise syntheses of key drug intermediates have further displayed the importance of this methodology.
Copper-Catalyzed Enantioselective Hydroalkoxylation of Alkenols for the Synthesis of Cyclic Ethers
Chen, Dake,Berhane, Ilyas A.,Chemler, Sherry R.
supporting information, p. 7409 - 7414 (2020/06/29)
The copper-catalyzed enantioselective intramolecular hydroalkoxylation of unactivated alkenes for the synthesis of tetrahydrofurans, phthalans, isochromans, and morpholines from 4- and 5-alkenols is reported. The substrate scope is complementary to existing enantioselective alkene hydroalkoxylations and is broad with respect to substrate backbone and alkene substitution. The asymmetric induction and isotopic labeling studies support a polar/radical mechanism involving enantioselective oxycupration followed by C-[Cu] homolysis and hydrogen atom transfer. Synthesis of the antifungal insecticide furametpyr was accomplished.
PdII-Catalyzed Oxidative Tandem aza-Wacker/Heck Cyclization for the Construction of Fused 5,6-Bicyclic N,O-Heterocycles
Ye, Chenghao,Kou, Xuezhen,Xia, Jingzhao,Yang, Guoqiang,Kong, Li,Wei, Quhao,Zhang, Wanbin
supporting information, p. 1897 - 1901 (2018/07/31)
A PdII-catalyzed oxidative tandem cyclization was developed for the construction of fused 5,6-bicyclic N, O-heterocycles. This reaction was enabled by the combined use of a 3-methylpyridine ligand and pentafluorobenzoic acid additive. A range of heterocyclic products with different substituents could be prepared in moderate to good yields via this methodology. Several transformations, including a scaled-up preparation of product 2 a, were also carried out showing the good applicability of our methodology.
Ruthenium-Catalyzed Enantioselective Hydrogenation/Lactonization of 2-Acylarylcarboxylates: Direct Access to Chiral 3-Substituted Phthalides
Lu, Bin,Zhao, Mengmeng,Ding, Guangni,Xie, Xiaomin,Jiang, Lili,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
, p. 3989 - 3996 (2017/09/13)
Highly enantioselective tandem hydrogenation/lactonization of various 2-acylarylcarboxylates including 2-aroylarylcarboxylates were realized by using [RuCl(benzene)(S)-SunPhos]Cl as the catalyst under mild reaction conditions. Excellent enantioselectivities (up to 99.6 % ee) and activities (S/C=1000) were obtained. This convenient and practical method enables a direct access to a series of highly optically pure 3-substituted phthalides that are very important molecules as valuable pharmacological compounds and diversified synthons for medicinal chemistry. Moreover, a gram-scale reaction was performed to further demonstrate the practicality of this approach.
Enantioselective Palladium(II)-Catalyzed Intramolecular Aminoarylation of Alkenes by Dual N?H and Aryl C?H Bond Cleavage
Zhang, Wen,Chen, Pinhong,Liu, Guosheng
supporting information, p. 5336 - 5340 (2017/04/27)
An asymmetric palladium-catalyzed intramolecular oxidative aminoarylation of alkenes has been developed with quinoline–oxazoline chiral ligands and Ag2CO3 as the oxidant. Various indolines containing a quaternary stereogenic center were synthesized in high yield with excellent enantioselectivity. Preliminary mechanistic studies suggest that the addition of a catalytic amount of phenylglyoxylic acid significantly accelerates the reaction and slightly enhances the enantioselectivity.
Preparation of isoindolinones via a palladium-catalyzed diamination
Li, Yu,Kou, Xuezhen,Ye, Chenghao,Zhang, Xinghua,Yang, Guoqiang,Zhang, Wanbin
supporting information, p. 285 - 288 (2017/01/03)
A Pd(II)-catalyzed cyclization using oxidative olefin diamination was developed for the preparation of isoindolinones from ortho-olefinic N-methoxybenzamides. Using the optimized reaction conditions, the desired products were obtained in up to 90% yield using NFSI as the oxidant. This reaction provides an efficient and direct access to isoindolinones with amine functionality, an important drug skeleton.
Palladium-Catalyzed Aerobic Aminooxygenation of Alkenes for Preparation of Isoindolinones
Kou, Xuezhen,Li, Yu,Wu, Liang,Zhang, Xinghua,Yang, Guoqiang,Zhang, Wanbin
supporting information, p. 5566 - 5569 (2015/12/01)
A palladium-catalyzed intramolecular isoindolinone-forming aminooxygenation of alkenes with 1 atm of oxygen as oxidant is reported. A variety of functionalized alkenes and carboxylic acids can be used, and high yields were observed. Preliminary mechanistic studies revealed that the aminooxygenation products were formed through the oxidation of a C-PdII species using a strong oxidant, peroxide, which is generated in situ from a Pd(OAc)2/bpy/O2/HOAc catalytic system.
Carboxy-directed asymmetric hydrogenation of α-alkyl-α-aryl terminal olefins: Highly enantioselective and chemoselective access to a chiral benzylmethyl center
Yang, Shuang,Zhu, Shou-Fei,Guo, Na,Song, Song,Zhou, Qi-Lin
supporting information, p. 2049 - 2052 (2014/03/21)
A carboxy-directed asymmetric hydrogenation of α-alkyl-α-aryl terminal olefins was developed by using a chiral spiro iridium catalyst, providing a highly efficient approach to the compounds with a chiral benzylmethyl center. The carboxy-directed hydrogenation prohibited the isomerization of the terminal olefins, and realized the chemoselective hydrogenation of various dienes. The concise enantioselective syntheses of (S)-curcudiol and (S)-curcumene were achieved by using this catalytic asymmetric hydrogenation as a key step.
Copper-mediated/catalyzed oxyalkylation of alkenes with alkylnitriles
Bunescu, Ala,Wang, Qian,Zhu, Jieping
supporting information, p. 14633 - 14636 (2015/01/09)
A copper-promoted oxyalkylation of alkenes with alkylnitriles has been developed. The protocol provides rapid access to phthalides (γ-lactones) or isochromanones (d-lactones) via the formation of a C(sp3)-C(sp3) and a C(sp3)-O bond with the generation of up to two quaternary carbon atoms. Mechanistic studies suggest that this reaction is initiated by the formation of the C(sp3)-C(sp3) bond rather than the C(sp3)-O bond. Catalytic conditions were subsequently developed using carboxylic acid as an internal nucleophile.
An asymmetric aerobic aza-Wacker-type cyclization: Synthesis of isoindolinones bearing tetrasubstituted carbon stereocenters
Yang, Guoqiang,Shen, Chaoren,Zhang, Wanbin
supporting information, p. 9141 - 9145 (2012/11/07)
It's all in the solvent: An enantioselective variant of an aza-Wacker-type cyclization that gives isoindolinones containing tetrasubstituted carbon centers α to the nitrogen atom has been developed (see scheme; tfa=trifluoroacetate). The use of a highly coordinating solvent is crucial for the activity of the catalyst and the stereoselectivity the reaction (up to 99 % ee). Copyright
