82632-38-0Relevant articles and documents
Chemoselective Cross-Coupling between Two Different and Unactivated C(aryl)-O Bonds Enabled by Chromium Catalysis
Tang, Jinghua,Liu, Liu Leo,Yang, Shangru,Cong, Xuefeng,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 7715 - 7720 (2020/05/20)
We report here the first example of cross-coupling between two different and unactivated C(aryl)-O bonds with chromium catalysis. The combination of a low-cost Cr(II) salt, 4,4′-di-tert-butyl-2,2′-dipyridyl (dtbpy) as the ligand, and magnesium as the reductant shows high reactivity in promoting the reductive cross-coupling of aryl methyl ether derivatives with aryl esters by cleavage and coupling of two different C(aryl)-O bonds under mild conditions. The formation of active low-valent Cr species by reduction of CrCl2 with Mg can be considered, which prefers to initially activate the C(aryl)-O bond of phenyl methyl ether with the chelation help of dtbpy and an o-imine auxiliary. The subsequent consecutive reduction, second C(aryl)-O activation, and reductive elimination allow for the achievement of selective cross-coupling of C(aryl)-O/C(aryl)-O bonds.
Carbonylation Access to Phthalimides Using Self-Sufficient Directing Group and Nucleophile
Ji, Fanghua,Li, Jianxiao,Li, Xianwei,Guo, Wei,Wu, Wanqing,Jiang, Huanfeng
, p. 104 - 112 (2018/02/19)
Herein we report a novel palladium-catalyzed oxidative carbonylation reaction for the synthesis of phthalimides with high atom- and step-economy. In our strategy, the imine and H2O, which are generated in situ from the condensation of aldehyde and amine, serve as self-sufficient directing group and nucleophile, respectively. This method provides rapid access to phthalimides starting from readily available materials in a one-pot manner. Various phthalimide derivatives are constructed efficiently, including medicinally and biologically active phthalimide-containing compounds.
Chromium-Catalyzed, Regioselective Cross-Coupling of C-O Bonds by Using Organic Bromides as Reactants
Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 2577 - 2580 (2017/09/28)
We report a chromium-catalyzed cross-coupling of C-O bonds with widely accessible organic bromides as reactants for the preparation of ortho -arylated or -alkylated aromatic aldehydes at room temperature. The use of metallic magnesium is essential for the reaction to occur, giving it an advantage over previous reactions involving Grignard reagents that have to be prepared separately from organic halides before the coupling.
Formal Ir-Catalyzed Ligand-Enabled Ortho and Meta Borylation of Aromatic Aldehydes via in Situ-Generated Imines
Bisht, Ranjana,Chattopadhyay, Buddhadeb
supporting information, p. 84 - 87 (2016/01/25)
The ligand-enabled development of ortho and meta C-H borylation of aromatic aldehydes is reported. It was envisaged that while ortho borylation could be achieved using tert-butylamine as the traceless protecting/directing group, meta borylation proceeds via an electrostatic interaction and a secondary interaction between the ligand of the catalyst and the substrate. These ligand-substrate electrostatic interactions and secondary B-N interactions provide an unprecedented controlling factor for meta-selective C-H activation/borylation.
Regio- and Chemoselective Kumada-Tamao-Corriu Reaction of Aryl Alkyl Ethers Catalyzed by Chromium under Mild Conditions
Cong, Xuefeng,Tang, Huarong,Zeng, Xiaoming
supporting information, p. 14367 - 14372 (2015/12/01)
Acting as an environmentally benign synthetic tool, the cross-coupling reactions with aryl ethers via C-O bond activation have attracted broad interest. However, the functionalizations of C-O bonds are mainly limited to nickel catalysis, and selectivity has long been a prominent challenge when several C-O bonds are present in the one molecule. We report here the first chromium-catalyzed selective cross-coupling reactions of aryl ethers with Grignard reagents by the cleavage of C-O(alkyl) bonds. Diverse transformations were achieved using simple, inexpensive chromium(II) precatalyst combining imino auxiliary at room temperature. It offers a new avenue for buildup functionalized aromatic aldehydes with high efficiency and selectivity.
Stereoselective synthesis of trans- and cis-2-aryl-3-(hydroxymethyl) aziridines through transformation of 4-aryl-3-chloro-β-lactams and study of their ring opening
D'Hooghe, Matthias,Mollet, Karen,Dekeukeleire, Stijn,De Kimpe, Norbert
body text, p. 607 - 615 (2010/04/30)
trans- and cis-1-Alkyl-4-aryl-3-chloroazetidin-2-ones, prepared through cyclocondensation of chloroketene and the appropriate imines in a diastereoselective way, were transformed into the corresponding non-activated trans- and cis-2-aryl-3-(hydroxymethyl)aziridines via reductive ring contraction using LiAlH4 in Et2O. Furthermore, trans-2-aryl-3- (hydroxymethyl)aziridines were transformed into 2-amino-3-arylpropan-1-ols and anti-2-amino-3-aryl-3-methoxypropan-1-ols by means of an unprecedented ring opening by LiAlH4 and by MeOH, respectively. cis-2-Aryl-3- (hydroxymethyl)aziridines were shown to be highly reluctant to undergo ring opening by LiAlH4 and MeOH under similar reaction conditions.
Highly efficient oxidation of amines to imines by singlet oxygen and its application in ugi-type reactions
Jiang, Gaoxl,Chen, Jian,Huang, Jie-Sheng,Che, Chi-Ming
supporting information; experimental part, p. 4568 - 4571 (2009/12/07)
A variety of secondary benzylic amines were oxidized to imines in 90% to >99% yields by singlet oxygen generated from oxygen and a porphyrin photosensitizer. On the basis of these reactions, a protocol was developed for oxidative Ugi-type reactions with singlet oxygen as the oxidant. This protocol has been used to synthesize C1- and N-functionalized benzylic amines in up to 96% yields.
Benzaldimines as ligands for palladium in Suzuki-Miyaura reactions
Srimani, Dipankar,Sarkar, Amitabha
supporting information; experimental part, p. 6304 - 6307 (2009/04/06)
Schiff bases derived from substituted benzaldehydes are effective ligands for palladium(0) in the Suzuki-Miyaura coupling of phenylboronic acid with aryl, benzyl and allyl bromides under mild conditions.
