7073-70-3Relevant articles and documents
Bimetal Cooperatively Catalyzed Arylalkynylation of Alkynylsilanes
Chen, Xing,Li, Mengke,Liu, Zhipeng,Yang, Can,Xie, Haisheng,Hu, Xinwei,Su, Shi-Jian,Jiang, Huanfeng,Zeng, Wei
supporting information, p. 6724 - 6728 (2021/09/08)
An unprecedented Pd/Rh cooperatively catalyzed arylalkynylation of alkynylsilanes was developed to merge an alkynylidene moiety with benzosilacycle. These silaarenes possess a particular aggregation-induced emission behavior. Mechanistic investigations demonstrate that the relay trimetallic transmetalation plays a pivotal role in governing this transformation.
Substituted 9-Anthraldehydes from Dibenzocycloheptanol Epoxides via Acid-Catalyzed Epoxide Opening/Semipinacol Rearrangement
Phumjan, Tanawat,Songthammawat, Poramate,Jongcharoenkamol, Jira,Batsomboon, Paratchata,Ruchirawat, Somsak,Ploypradith, Poonsakdi
, p. 13322 - 13349 (2021/09/13)
Starting from benzaldehyde derivatives, the corresponding dibenzocycloheptenol could be prepared in five steps. Under both substrate (secondary vs tertiary alcohol and the substituents on the aromatic ring(s)) and condition control, the subsequent epoxidation and acid-catalyzed epoxide opening/semipinacol rearrangement/aromatization afforded the corresponding 9-anthraldehydes in good yields, up to 88% over two steps. The presence of the electron-withdrawing group(s) on the aromatic ring(s) suppressed the rate of the epoxidation while the subsequent semipinacol rearrangement step required heating; the presence of the electron-donating group(s), on the other hand, frequently led to the decomposition during the epoxidation. From the mechanistic studies, the semipinacol rearrangement of the epoxide could precede the ionization at the bisbenzylic position, yielding the aldehyde intermediate. The ensuing dehydrative aromatization led to the formation of 9-anthraldehyde. Conversely, nucleophilic addition to the aldehyde and dehydrative aromatization with concomitant loss of formic acid led to anthracene.
1,3-Difunctionalization of β-alkyl nitroalkenes via combination of Lewis base catalysis and radical oxidation
Wang, Ye,Zheng, Lei,Shi, Xiaodong,Chen, Yunfeng
supporting information, p. 886 - 889 (2021/02/01)
Upon treatment with a Lewis base catalyst, β-alkyl-substituted nitroalkenes could be readily converted into allylic nitro compounds. Examples of either C-1 or C-3 functionalization methods have been reported through nitro-elimination, giving alkene products. In this work, successful 1,3-difunctionalization was achieved through a synergetic Lewis base catalysis and TBHP radical oxidation, giving vinylic alkoxyamines in good to excellent yields. This work further extended the general synthetic application of β-alkyl nitroalkenes.
A Transient Directing Group Strategy Enables Enantioselective Multicomponent Organofluorine Synthesis
Liu, Zhonglin,Oxtoby, Lucas J.,Liu, Mingyu,Li, Zi-Qi,Tran, Van T.,Gao, Yang,Engle, Keary M.
supporting information, p. 8962 - 8969 (2021/07/01)
The vicinal fluorofunctionalization of alkenes represents an expedient strategy for converting feedstock olefins into valuable fluorinated molecules and as such has garnered significant attention from the synthetic community; however, current methods remain limited in terms of scope and selectivity. Here we report the site-selective palladium-catalyzed three-component coupling of alkenylbenzaldehydes, arylboronic acids, and N-fluoro-2,4,6-trimethylpyridinium hexafluorophosphate facilitated by a transient directing group. The synthetically enabling methodology constructs vicinal stereocenters with excellent regio-, diastereo-, and enantioselectivities, forging products that map onto bioactive compounds.
Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
Ding, Du,Jiang, Hua-Jie,Wang, Tao,Wu, Xiang,Zhang, Ying,Zhao, Li-Ping
supporting information, 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.
Rh-Catalyzed Asymmetric Hydrogenation of α,β- and β,β-Disubstituted Unsaturated Boronate Esters
Hou, Guohua,Shen, Xin,Yan, Qiaozhi,Zi, Guofu
supporting information, (2020/05/08)
A highly enantioselective hydrogenation of α,β-unsaturated boronate esters catalyzed by Rh-(S)-DTBM-Segphos complex has been developed. Both (Z)-α,β- and β,β-disubstituted substrates can be successfully hydrogenated to afford chiral boronates with excellent enantioselectivities, up to 98 % ee. Furthermore, the obtained chiral boronate esters, as important versatile synthetic intermediates are successfully transformed to the corresponding chiral alcohols, amines and other important derivatives with maintained enantioselectivities.
Preparation method of silicon spiro compound (by machine translation)
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Paragraph 0222-0224, (2020/06/17)
The invention discloses a preparation method of a silicon spiro compound. The invention provides a preparation method of a silicon spiro compound as shown in a formula II, which comprises the following steps: in a solvent, a compound represented by the formula III is subjected to cyclization reaction under the presence of a monovalent rhodium catalyst and a phosphine ligand to obtain the silicon spiro compound as shown in the formula II. The preparation method of the silicon spiro compound can be simple. , The establishment of the silicon spiro compound is realized conveniently and efficiently. (by machine translation)
Consecutive borylcupration/C-C coupling of ?-alkenyl aldehydes towards diastereoselective 2-(borylmethyl)cycloalkanols
Carbó, Jorge J.,Fernández, Elena,Maza, Ricardo J.,Royes, Jordi
supporting information, p. 5973 - 5976 (2020/06/05)
Copper(i) catalyzes the borylative cyclization of ?-alkenyl aldehydes through chemo- and regioselective addition of Cu-B to C?C and concomitant intramolecular 1,2-addition of Cu-C on C?O. The products are formed in an exclusive diastereoselective manner and computational analysis identifies the key points for the observed chemo- and diastereoselectivity.
Asymmetric Synthesis and Application of Chiral Spirosilabiindanes
Chang, Xin,Chen, Hong-Chao,Li, Chuan-Ying,Ma, Pei-Long,Wang, Peng
supporting information, p. 8937 - 8940 (2020/04/30)
Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh-catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh-catalyzed hydrogenation and a Pd-catalyzed intramolecular carboamination.
Rhodium-Catalyzed Intermolecular Cyclopropanation of Benzofurans, Indoles, and Alkenes via Cyclopropene Ring Opening
Jeyaseelan, Rubaishan,Lautens, Mark,Ross, Rachel J.
supporting information, (2020/06/29)
The generation of metal carbenoids via ring opening of cyclopropenes by transition metals offers a simple entry into highly reactive intermediates. Herein, we describe a diastereoselective intermolecular rhodium-catalyzed cyclopropanation of heterocycles and alkenes using cyclopropenes as carbene precursors with a low loading of a commercially available rhodium catalyst. The reported method is scalable and could be performed with catalyst loadings as low as 0.2 mol %, with no impact to the reaction yield or selectivity.
