22955-78-8Relevant academic research and scientific papers
cis-Fused hexahydro-4aH-indeno[1,2-b]pyridines: Transformation of bridgehead ester group and conversion to tricyclic analogues of NK-1 and dopamine receptor ligands
De Wit, Tom,Van Emelen, Kristof,Maertens, Faye,Hoornaert, Georges J,Compernolle, Frans
, p. 4919 - 4922 (2001)
The bridgehead ester group of cis-fused methyl 2-oxo-9b-phenyl-1,2,3,4,5,9b-hexahydro-4aH-indeno[1,2-b]pyridine-4a- carboxylates obtained via an intramolecular Ritter reaction, was transformed into acid, alcohol, aldehyde, and amine groups. Further elaboration afforded conformationally constrained tricyclic analogues of NK-1 antagonists and a bicyclic dopamine receptor ligand.
Synthesis of α-Quaternary Bicyclo[1.1.1]pentanes through Synergistic Organophotoredox and Hydrogen Atom Transfer Catalysis
Anderson, Edward A.,Frank, Nils,Mousseau, James J.,Nugent, Jeremy,Sterling, Alistair J.
supporting information, p. 8628 - 8633 (2021/11/17)
Bicyclo[1.1.1]pentanes (BCPs) are important in drug design as sp3-rich bioisosteres of arenes and tert-butyl groups; however, the preparation of BCPs with adjacent quaternary carbons is barely known. We report a facile synthesis of α-quaternary BCPs using organophotoredox and hydrogen atom transfer catalysis in which α-keto radicals, generated through oxidation of β-ketocarbonyls, undergo efficient addition to [1.1.1]propellane. The BCP products can be transformed into a variety of useful derivatives, including enantioenriched BCPs featuring α-quaternary stereocenters.
Zirconium-Salan Catalyzed Enantioselective α-Hydroxylation of β-Keto Esters
Chen, Jie,Gu, Haiyang,Zhu, Xueying,Nam, Wonwoo,Wang, Bin
supporting information, p. 2976 - 2983 (2020/07/06)
We report herein the development of enantioselective and scalable α-hydroxylation of 1-indanone-derived β-keto esters by Zr(IV) complexes bearing readily available C2-symmetric salan ligands and cumene hydroperoxide as an oxidant, affording synthetically valuable hydroxylation products in high yields (up to 99percent) with excellent enantioselectivities (up to 99percent ee) under mild reaction conditions. In mechanistic studies, we have shown that (1) a Zr(IV)-salan complex was generated in situ as the active catalyst responsible for the chiral induction, (2) the transfer of the electrophilic fragment from cumene hydroperoxide to the Zr(IV)-bound enolate was accompanied by a heterolytic O?O bond cleavage, and (3) the formation of hydrogen bond between the amine hydrogen atom(s) of the salan ligand and the hydroxy group of cumene hydroperoxide was significant for stabilizing the stereocontrolled transition state and improving the enantioselectivity. (Figure presented.).
Ring-Strain-Enabled Catalytic Asymmetric Umpolung C-O Bond-Forming Reactions of 1,2-Oxazetidines for the Synthesis of Functionalized Chiral Ethers
Wu, Binyu,Yang, Jinggang,Gao, Min,Hu, Lin
supporting information, p. 5561 - 5566 (2020/07/14)
An unprecedented catalytic asymmetric umpolung C-O bond-forming reaction of N-nosyl 1,2-oxazetidines with β-keto esters has been achieved in the presence of a chiral phase-transfer catalyst, allowing access to a range of highly functionalized chiral ethers bearing quaternary and no adjacent stereogenic centers with high yields, excellent enantioselectivities, and diastereoselectivities (up to 97percent ee and 20:1 dr). These versatile products could be flexibly transformed into biologically important chiral fused and spiro morpholines in two steps.
Catalytic asymmetric fluorination of Alkyl 1-indanone-2-carboxylates Ruled by Pybox-Eu(III) Combination
Granados, Albert,Sarró, Pau,Vallribera, Adelina
supporting information, (2019/04/03)
A highly enantioselective catalytic method for the synthesis of quaternary α-fluoro derivatives of 3-oxo esters is described. The reaction uses europium (III) triflate and commercially available chiral pybox-type C2-symmetric ligand. Excellent results in
Lanthanum-Catalyzed Enantioselective Trifluoromethylation by Using an Electrophilic Hypervalent Iodine Reagent
Granados, Albert,Rivilla, Iván,Cossío, Fernando P.,Vallribera, Adelina
supporting information, p. 8214 - 8218 (2019/05/15)
A highly enantioselective catalytic method for the synthesis of quaternary α-trifluoromethyl derivatives of 3-oxo esters is described. The reaction uses lanthanum(III) triflate and chiral PyBOX-type C2-symmetric ligands to generate intermediate LaIII complexes that incorporate an enolate moiety of the starting 3-oxo ester and the trifluoromethylation transfer reagent. The enantioselectivity of the reaction stems from the efficient blockage of one of the prochiral faces of the LaIII enolate by one unit of the C2-symmetric ligand.
Chiral N,N'-Dioxide Organocatalyzed Asymmetric Electrophilic α-Cyanation of β-Keto Esters and β-Keto Amides
Ma, Baiwei,Lin, Xiaobin,Lin, Lili,Feng, Xiaoming,Liu, Xiaohua
, p. 701 - 708 (2017/04/26)
An enantioselective electrophilic α-cyanation of 1-indanone-derived β-keto esters and β-keto amides using a hypervalent iodine as the cyanide-transfer reagent was realized. A chiral N,N'-dioxide was used as the efficient bifunctional organocatalyst in the presence of inorganic base, which gave the corresponding α-cyano dicarbonyl compounds in yields of 50-99% with good enantioselectivities (87-97% ee).
Enantioselective electrophilic cyanation of β-keto amides catalysed by a cinchona organocatalyst
Karmaker, Pran Gopal,Qiu, Jiashen,Wu, Di,Reng, Mengmeng,Yang, Zhuo,Yin, Hongquan,Chen, Fu-Xue
supporting information, p. 7753 - 7757 (2017/10/06)
An operationally simple protocol for the enantioselective electrophilic α-cyanation of β-keto amides catalyzed by cinchona-derived catalysts has been demonstrated. The resulting products could be obtained with good to high enantioselectivities (up to 88% ee) and with excellent yields (up to 94%) by employing the mild active 4-acetylphenyl cyanate as the cationic cyano source in the catalytic asymmetric α-cyanation reaction.
Trimethylchlorosilane-Mediated Mild α-Chlorination of 1,3-Dicarbonyl Compounds Promoted by Phenyliodonium Diacetate
Chong, Siying,Su, Yingpeng,Wu, Lili,Zhang, Weigang,Ma, Junyan,Chen, Xiaowei,Huang, Danfeng,Wang, Ke-Hu,Hu, Yulai
supporting information, p. 1359 - 1370 (2016/05/02)
Trimethylchlorosilane was used as chlorine source for the α-chlorination of 1,3-dicarbonyl compounds with phenyliodonium diacetate as oxidant at room temperature. The reaction allows the selective synthesis of α-monochlorinated products from different kinds of 1,3-dicarbonyl compounds in good yield. The potential possibility of this conversion for bromination has also been investigated.
Bifunctional Thiourea Catalyzed Asymmetric Mannich Reaction Using Trifluoromethyl Aldimine as Trifluoromethyl Building Blocks
Ji, Shilong,Alkhalil, Ahmed Ebrahim,Su, Yingpeng,Xia, Xiaowen,Chong, Siying,Wang, Ke-Hu,Huang, Danfeng,Fu, Ying,Hu, Yulai
supporting information, p. 1725 - 1731 (2015/07/20)
An efficient bifunctional thiourea catalyzed asymmetric Mannich reaction with trifluoromethyl aldimine as trifluoromethyl building block was achieved to give the products in good diastereoselectivity and enantioselectivity.
