773097-04-4Relevant articles and documents
Near-Unity Triplet Generation Promoted via Spiro-Conjugation
Casanova, David,Chen, Jinquan,Jiang, Yanrong,Lu, Xicun,Lv, Meng,Sandoval-Salinas, María E.,Sun, Haitao,Sun, Zhenrong,Xu, Jianhua,Yang, Youjun
supporting information, (2021/12/14)
An intersystem crossing (ISC) rate constant of 1.0×1011 s?1 was previously registered with a spiro-bis-benzophenone scaffold. Triplet generation efficiency could be further enhanced by stabilizing the spiro-charge-transfer (CT) state
Catalytic Synthesis of 8-Membered Ring Compounds via Cobalt(III)-Carbene Radicals
Lankelma, Marianne,Zhou, Minghui,de Bruin, Bas,van der Vlugt, Jarl Ivar
supporting information, p. 11073 - 11079 (2020/04/29)
The metalloradical activation of o-aryl aldehydes with tosylhydrazide and a cobalt(II) porphyrin catalyst produces cobalt(III)-carbene radical intermediates, providing a new and powerful strategy for the synthesis of medium-sized ring structures. Herein we make use of the intrinsic radical-type reactivity of cobalt(III)-carbene radical intermediates in the [CoII(TPP)]-catalyzed (TPP=tetraphenylporphyrin) synthesis of two types of 8-membered ring compounds; novel dibenzocyclooctenes and unprecedented monobenzocyclooctadienes. The method was successfully applied to afford a variety of 8-membered ring compounds in good yields and with excellent substituent tolerance. Density functional theory (DFT) calculations and experimental results suggest that the reactions proceed via hydrogen atom transfer from the bis-allylic/benzallylic C?H bond to the carbene radical, followed by two divergent processes for ring-closure to the two different types of 8-membered ring products. While the dibenzocyclooctenes are most likely formed by dissociation of o-quinodimethanes (o-QDMs) which undergo a non-catalyzed 8π-cyclization, DFT calculations suggest that ring-closure to the monobenzocyclooctadienes involves a radical-rebound step in the coordination sphere of cobalt. The latter mechanism implies that unprecedented enantioselective ring-closure reactions to chiral monobenzocyclooctadienes should be possible, as was confirmed for reactions mediated by a chiral cobalt-porphyrin catalyst.
Efficient synthesis of dibenzazepine lactams via a sequential Pd-catalyzed amination and aldol condensation reaction
Song, Ha-Jeong,Yoon, Eunyoung,Heo, Jung-Nyoung
supporting information, (2019/12/27)
A simple and efficient reaction was developed for the synthesis of dibenzazepine lactam derivatives. The core 7-membered azepine ring was formed by a stepwise sequence involving a palladium-catalyzed amination and an aldol condensation.
Copper-Catalyzed Cope-Type Hydroamination of Nonactivated Olefins toward Cyclic Nitrones: Scope, Mechanism, and Enantioselective Process Development
Zhang, Mengru,Liu, Shuang,Li, Hexin,Guo, Yajing,Li, Na,Guan, Meihui,Mehfooz, Haroon,Zhao, Jinbo,Zhang, Qian
supporting information, p. 12620 - 12627 (2019/09/16)
The catalytic synthesis of cyclic nitrones, an important type of functional molecules for both synthetic chemistry and related fields, remains underdeveloped. Herein we report the copper-catalyzed Cope-type hydroamination of oximes with pendant nonactivated olefins, which enables facile access to a series of five- and six-membered cyclic nitrones under mild conditions. In this study, heterocycle-tethered oximes were employed in the Cope-type hydroamination reaction for the first time. High enantioselectivity was achieved for carbon-tethered γ,δ-vinyl oximes to afford enantioenriched five-membered cyclic nitrones. The results of preliminary mechanistic studies indicate a mononuclear catalytic species and a unified catalytic pathway over a large temperature range.
Catalytic Dibenzocyclooctene Synthesis via Cobalt(III)–Carbene Radical and ortho-Quinodimethane Intermediates
te Grotenhuis, Colet,van den Heuvel, Naudin,van der Vlugt, Jarl Ivar,de Bruin, Bas
supporting information, p. 140 - 145 (2017/12/13)
The metalloradical activation of ortho-benzallylaryl N-tosyl hydrazones with [Co(TPP)] (TPP=tetraphenylporphyrin) as the catalyst enabled the controlled exploitation of the single-electron reactivity of the redox non-innocent carbene intermediate. This method offers a novel route to prepare eight-membered rings, using base metal catalysis to construct a series of unique dibenzocyclooctenes through selective Ccarbene?Caryl cyclization. The desired eight-membered-ring products were obtained in good to excellent yields. A large variety of aromatic substituents are tolerated. The proposed reaction mechanism involves intramolecular hydrogen atom transfer (HAT) to CoIII–carbene radical intermediates followed by dissociation of an ortho-quinodimethane that undergoes 8π cyclization. The mechanism is supported by DFT calculations, and the presence of radical-type intermediates was confirmed by trapping experiments.
Intermolecular Dehydrative Coupling and Intramolecular Cyclization of Ruthenium Vinylidene Complexes Formed from Aromatic Propynes Containing Carbonyl Functionalities
Chia, Pi-Yeh,Kuo, Cheng-Chen,Huang, Shou-Ling,Liu, Yi-Hong,Liu, Ling-Kang,Lin, Ying-Chih
supporting information, p. 3885 - 3894 (2018/11/10)
A remarkable intermolecular dehydrative coupling reaction with the formation of a C?C bond was found for the vinylidene complex 2 a, yielding the dinuclear bisvinylidene complex 4 a. Complex 2 a containing 1-hydroxyindan moiety was first formed from the reaction of o-propynyl benzaldehyde 1 a with [Ru]–Cl ([Ru]=Cp(PPh3)2Ru) by a cyclization process. For analogous aldehyde 1 b containing an additional 1,3-dioxolane group on the aryl ring, similar intermolecular coupling yields the dinuclear bisvinylidene complex 4 b. However, the fluoro group on the aryl ring in aldehyde 1 c inhibits the coupling reaction, giving only the vinylidene complex 2 c. For the reactions of [Ru]–Cl in MeOH with compounds 1 f, 1 g and 1 h, each with a ketone functionality, cyclization gives vinylidene complexes 2 f, 2 g and 2 h, respectively. However, no similar intermolecular coupling was observed, instead, the intramolecular dehydration yields 8 f, 8 g and 8 h, respectively. In CDCl3, catalytic cyclization is observed for the o-propynylphenyl ketone 1 h with [Ru]–Cl at 50 °C giving the isochromene products 14 h. Furthermore, treatment of the o-propynylaryl α,β-unsaturated ketones 1 k–m and 1 n with [Ru]–Cl in MeOH affords the corresponding vinylidene complexes 10 k–m and 11 n each with 1-benzosuberone moiety in the presence of NH4PF6. These intramolecular cyclization products were formed by the addition of Cβ onto the terminal carbon of the alkene moiety. All these reaction products were characterized by spectroscopic methods. In addition, structures of complexes 4 a, and 10 l were confirmed by single crystal X-ray diffraction analysis.
TPZ, a bright centrosymmetric two-photon scaffold for bioimaging
Lei, Zuhai,Yue, Ping,Wang, Xueli,Li, Xinran,Li, Yi,He, Haihong,Luo, Xiao,Meng, Xiangming,Chen, Jinquan,Qian, Xuhong,Yang, Youjun
supporting information, p. 10938 - 10941 (2017/10/13)
The development of biocompatible two-photon fluorophores with a large absorption cross-section is challenging, despite the presence of theoretical guidelines. By rendering asymmetric PRODAN dye centrosymmetric, we designed and synthesized a novel class of two-photon fluorophores (TPZ). Their photophysical properties were investigated and their imaging potentials in cells, tissues and zebrafish were showcased.
Enantioselective Intramolecular Hydroacylation of Unactivated Alkenes: An NHC-Catalyzed Robust and Versatile Formation of Cyclic Chiral Ketones
Janssen-Müller, Daniel,Schedler, Michael,Fleige, Mirco,Daniliuc, Constantin G.,Glorius, Frank
supporting information, p. 12492 - 12496 (2015/10/12)
A highly enantioselective intramolecular N-heterocyclic carbene (NHC)-catalyzed hydroacylation reaction gives access to a range of cyclic ketones from unactivated olefin-substituted aldehydes (up to 99% ee). Remarkably, aliphatic aldehydes were also transformed efficiently in an NHC-catalyzed hydroacylation reaction for the first time. 100% Organic: A highly enantioselective N-heterocyclic carbene (NHC)-catalyzed intramolecular hydroacylation of aromatic and, more interestingly, aliphatic aldehydes with unactivated olefins offers access to a range of cyclic α-chiral ketones bearing quaternary centers. The reaction was found to be highly robust and proceeds with excellent yield in the presence of a diverse range of functional groups.
BORON-CONTAINING SMALL MOLECULES
-
Paragraph 0231, (2015/02/19)
This invention provides novel compounds of the following formula and pharmaceutical compositions containing such compounds.
Novel pyrrolobenzoxaboroles: Design, synthesis, and biological evaluation against Trypanosoma brucei
Wu, Puhua,Zhang, Jiong,Meng, Qingqing,Nare, Bakela,Jacobs, Robert T.,Zhou, Huchen
, p. 59 - 75 (2014/06/09)
Human African trypanosomiasis is a fatal parasitic infection caused by the protozoan Trypanosoma brucei. The development of novel antitrypanosomal agents is urgently needed. Here we report the synthesis and structure-activity relationship of a new class of benzoxaboroles as antitrypanosomal agents. These compounds showed antiparasitic IC50 values ranging from 4.02 to 0.03 μg/mL and satisfactory cytotoxicity profile. Three of the lead compounds were demonstrated to cure the parasitic infection in a murine acute infection model. The structure-activity relationship of the pyrrolobenzoxaboroles are also discussed.
