871563-46-1Relevant academic research and scientific papers
The intramolecular reaction of acetophenoneN-tosylhydrazone and vinyl: Br?nsted acid-promoted cationic cyclization toward polysubstituted indenes
Wang, Zhixin,Li, Yang,Chen, Fan,Qian, Peng-Cheng,Cheng, Jiang
, p. 1810 - 1813 (2021/02/27)
In the presence of TsNHNH2, a Br?nsted acid-promoted intramolecular cyclization ofo-(1-arylvinyl) acetophenone derivatives was developed, leading to polysubstituted indenes with complexity and diversity in moderate to excellent yields. In sharp contrast with either the radical or carbene involved cyclization of aldehydicN-tosylhydrazone with vinyl, a cationic cyclization pathway was involved, whereN-tosylhydrazone served as an electrophile and alkylation reagent during this transformation.
Asymmetric Halocyclizations of 2-Vinylbenzyl Alcohols with Chiral FLPs
Han, Caifang,Feng, Xiangqing,Du, Haifeng
supporting information, p. 7325 - 7329 (2021/10/01)
By the use of a chiral frustrated Lewis pair (FLP) consisting of a chiral-diene-derived borane and tBu3P as the catalyst, an asymmetric halocyclization of 2-vinylbenzyl alcohols with NBS or NIS was successfully realized. A variety of optically active 1,3-dihydroisobenofuran derivatives were obtained in high yields with up to 87% ee and could be conveniently converted to other useful chiral compounds.
Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
Wu, Xiang,Ding, Du,Zhang, Ying,Jiang, Hua-Jie,Wang, Tao,Zhao, Li-Ping
, p. 9680 - 9683 (2021/09/30)
We describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiralN-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline.
Construction of Partially Protected Nonsymmetrical Biaryldiols via Semipinacol Rearrangement of o-NQM Derived from Enynones
Wu, Feng,Cheng, Tairan,Zhu, Shifa
supporting information, p. 71 - 75 (2021/01/09)
The construction of partially protected nonsymmetrical biaryldiols catalyzed by AgBF4 has been achieved. The approach facilitates the formation of two new aryl rings and the introduction of two hydroxyl groups (one free and one TBS-protected) via the o-NQM generation/semipinacol rearrangement cascade, featuring high atom- and step-economy to afford a diverse array of partially protected nonsymmetrical biaryldiols under mild conditions.
A Strategy To Obtain o-Naphthoquinone Methides: Ag(I)-Catalyzed Cyclization of Enynones for the Synthesis of Benzo[ h]chromanes and Naphthopyryliums
Wu, Feng,Zhu, Shifa
supporting information, (2019/03/08)
A new strategy to obtain o-NQM intermediates through a ring-formation strategy by Ag(I)-catalyzed cyclization of 2-alkenylphenyl alkynyl ketones and its [4 + 2] annulations with styrenes has been developed. This reaction features high efficiency, mild reaction conditions, as well as flexible substitutions and atom economy. The obtained benzo[h]chromane products were further oxidized to naphthopyryliums, which displayed tunable photophysical properties.
Synthesis of isothiochromenes and 1,3-dihydrobenzo[c]thiophenes by iodine- and hydrobromic acid-mediated cyclizations of o-[(tert-butylsulfanyl)methyl)]styrenes
Kobayashi, Kazuhiro,Ueyama, Takuma,Horiuchi, Mai
, p. 2065 - 2079 (2017/11/21)
Methods for the syntheses of 4-substituted isothiochromenes and 1,1-disubstituted 1,3-dihydrobenzo[c]thiophenes have been developed. Thus, treatment of α-substituted o-[(tert-butylsulfanyl)methyl]styrenes, derived from α-substituted o-bromostyrenes using
Rhodium(II)- or Copper(I)-Catalyzed Formal Intramolecular Carbene Insertion into Vinylic C(sp2)?H Bonds: Access to Substituted 1H-Indenes
Zhou, Qi,Li, Shichao,Zhang, Yan,Wang, Jianbo
supporting information, p. 16013 - 16017 (2017/11/27)
A rhodium(II)- or copper(I)-catalyzed formal intramolecular carbene insertion into vinylic C(sp2)?H bonds is reported herein. This method provides straightforward access to 1H-indenes with high efficiency and excellent functional-group compatibility. Mechanistically, the reaction is proposed to involve the following sequence: metal carbene formation, intramolecular nucleophilic addition of the double bond to the electron-deficient carbene carbon atom, dearomatization, and finally a 1,5-H shift.
Asymmetric Induction in Hydroacylation by Cooperative Iminium Ion-Transition-Metal Catalysis
Rastelli, Ettore J.,Truong, Ngoc T.,Coltart, Don M.
supporting information, p. 5588 - 5591 (2016/11/17)
A new strategy for the rhodium-catalyzed enantioselective hydroacylation is described. This has been achieved through the merger of iminium ion catalysis and transition-metal catalysis such that asymmetric induction derives from a readily accessible, inexpensive chiral nonracemic secondary amine catalyst rather than a chiral nonracemic phosphine as is typical of conventional asymmetric hydroacylation methods.
Cobalt-catalyzed enantioselective intramolecular hydroacylation of ketones and olefins
Yang, Junfeng,Yoshikai, Naohiko
supporting information, p. 16748 - 16751 (2015/02/05)
Cobalt-chiral diphoshine catalytic systems promote intramolecular hydroacylation reactions of 2-acylbenzaldehydes and 2-alkenylbenzaldehydes to afford phthalide and indanone derivatives, respectively, in moderate to good yields with high enantioselectivities. The ketone hydroacylation did not exhibit a significant H/D kinetic isotope effect (KIE) with respect to the aldehyde C-H bond, indicating that C-H activation would not be involved in the rate-limiting step.
Hydroacylation of 2-vinyl benzaldehyde systems: An efficient method for the synthesis of chiral 3-substituted indanones
Kundu, Kousik,McCullagh, James V.,Morehead Jr., Andrew T.
, p. 16042 - 16043 (2007/10/03)
Asymmetric rhodium-catalyzed hydroacylation has been utilized in the synthesis of 3-substituted indanones with high conversions and enantioselectivity. The hydroacylation reaction of 2-vinyl benzaldehyde had been previously reported to give a low yield of indanone and an unidentified product. We have identified this compound as a dimer of the starting material. Substitution at the α-position of the 2-vinyl benzaldehyde substrates blocks the competitive dimerization reaction and allows the reaction to proceed with yields generally greater than 90%. Utilization of BINAP as a chiral ligand results in good chemical yields and enantioselectivity greater than 95% in most cases. Copyright
