7706-83-4Relevant academic research and scientific papers
Carbene-Catalyzed Formal [3+3] Cycloaddition Reaction for Access to Substituted 2-Phenylbenzothiazoles
Ni, Zhibin,Mou, Chengli,Zhu, Xun,Qi, Puying,Yang, Song,Chi, Yonggui Robin,Jin, Zhichao
supporting information, p. 492 - 495 (2020/01/24)
A carbene-catalyzed oxidative cycloaddition reaction is developed for efficient access to multi-functionalized 2-phenylbenzothiazoles. A broad scope of heavily substituted arenes bearing 2-benzothiazole groups have been prepared in good to excellent yields. The remote C(sp2)–H bond in the substituted arene products can be activated by Pd catalysts in regio-selective fashion with the direction of the 2-benzothiazole groups.
Catalytic Asymmetric Transfer Hydrogenation of trans-Chalcone Derivatives Using BINOL-derived Boro-phosphates
Na, Fei,Lopez, Susana S.,Beauseigneur, Alice,Hernandez, Lucas W.,Sun, Zhuoxin,Antilla, Jon C.
supporting information, p. 5953 - 5957 (2020/08/12)
Chiral phosphoric-acid-catalyzed asymmetric reductions of trans-chalcones have been investigated in this work. A BINOL-derived boro-phosphate-catalyzed asymmetric transfer hydrogenation of the carbon-carbon double bond of trans-chalcone derivatives employing borane as a hydride source was realized. This methodology provides a convenient procedure to access chiral dihydrochalone derivatives in high yields and with high enantioselectivities under mild conditions.
Synergistic N-Heterocyclic Carbene/Palladium-Catalyzed [3 + 2] Annulation of Vinyl Enolates with 1-Tosyl-2-vinylaziridine
Gao, Jian,Zhang, Jianming,Fang, Shuaishuai,Feng, Jie,Lu, Tao,Du, Ding
supporting information, p. 7725 - 7729 (2020/10/09)
The synergistic combination of N-heterocyclic carbene organocatalysis and transition-metal catalysis for a formal [3 + 2] annulation between 3-substituted but-2-enoates and 1-tosyl-2-vinylaziridine was developed. This cooperative strategy provides a facile and efficient access to various functionalized (E)-3-ethylidene-4-vinylpyrrolidin-2-ones in a regioselective and stereoselective manner. The preliminary asymmetric studies were also performed, which indicated a potential for enantioselective annulation of vinyl enolate intermediates with transition-metal-π-allyl species.
Pd-Catalyzed decarboxylative cross-coupling reactions of epoxides with α,β-unsaturated carboxylic acids
Lu, Xiao-Yu,Li, Jin-Song,Wang, Shi-Qun,Zhu, Yu-Jing,Li, Yue-Ming,Yan, Lu-Yu,Li, Jia-Mei,Wang, Jin-Yu,Zhou, Hai-Pin,Ge, Xiu-Tao
supporting information, p. 11123 - 11126 (2019/09/20)
A Pd-catalyzed decarboxylative cross-coupling of α,β-unsaturated carboxylic acids with cyclic and acyclic epoxides has been developed. Both β-monosubstituted and β-disubstituted unsaturated carboxylic acids, as well as conjugated diene unsaturated carboxylic acids are suitable reaction substrates. Substituted homoallylic alcohols were obtained in moderate to good yields. The product was obtained as a mixture of diastereomers favoring the anti diastereomer of the cyclic epoxides. This work provides a method for the modification of complex organic molecules containing α,β-unsaturated carboxylic acids.
Highly Selective and Catalytic Generation of Acyclic Quaternary Carbon Stereocenters via Functionalization of 1,3-Dienes with CO2
Chen, Xiao-Wang,Zhu, Lei,Gui, Yong-Yuan,Jing, Ke,Jiang, Yuan-Xu,Bo, Zhi-Yu,Lan, Yu,Li, Jing,Yu, Da-Gang
, p. 18825 - 18835 (2019/11/28)
The catalytic asymmetric functionalization of readily available 1,3-dienes is highly important, but current examples are mostly limited to the construction of tertiary chiral centers. The asymmetric generation of acyclic products containing all-carbon quaternary stereocenters from substituted 1,3-dienes represents a more challenging, but highly desirable, synthetic process for which there are very few examples. Herein, we report the highly selective copper-catalyzed generation of chiral all-carbon acyclic quaternary stereocenters via functionalization of 1,3-dienes with CO2. A variety of readily available 1,1-disubstituted 1,3-dienes, as well as a 1,3,5-triene, undergo reductive hydroxymethylation with high chemo-, regio-, E/Z-, and enantioselectivities. The reported method features good functional group tolerance, is readily scaled up to at least 5 mmol of starting diene, and generates chiral products that are useful building blocks for further derivatization. Systemic mechanistic investigations using density functional theory calculations were performed and provided the first theoretical investigation for an asymmetric transformation involving CO2. These computational results indicate that the 1,2-hydrocupration of 1,3-diene proceeds with high π-facial selectivity to generate an (S)-allylcopper intermediate, which further induces the chirality of the quaternary carbon center in the final product. The 1,4-addition of an internal allylcopper complex, which differs from previous reports involving terminal allylmetallic intermediates, to CO2 kinetically determines the E/Z- and regioselectivity. The rapid reduction of a copper carboxylate intermediate to the corresponding silyl-ether in the presence of Me(MeO)2SiH provides the exergonic impetus and leads to chemoselective hydroxymethylation rather than carboxylation. These results provide new insights for guiding further development of asymmetric C-C bond formations with CO2
Construction of Multi-Substituted Benzenes via NHC-Catalyzed Reactions of Carboxylic Esters
Wu, Jichang,Mou, Chengli,Chi, Yonggui Robin
, p. 333 - 337 (2018/03/07)
A carbene-catalyzed ester activation reaction for the synthesis of multi-substituted benzenes is developed. Tetra-substituted benzene compounds are efficiently synthesized through this methodology. Compared with aldehyde substrates used in previous reports, the ester substrates used here are much more readily available and inexpensive. In addition, the TEMPO oxidant used here is more inexpensive than the quinones commonly used in related carbene-catalyzed reactions.
Carbene-catalyzed enal γ-carbon addition to α-ketophosphonates for enantioselective access to bioactive 2-pyranylphosphonates
Sun, Jun,He, Fangcheng,Wang, Zhongyao,Pan, Dingwu,Zheng, Pengcheng,Mou, Chengli,Jin, Zhichao,Chi, Yonggui Robin
supporting information, p. 6040 - 6043 (2018/06/18)
A carbene-catalyzed enantioselective [4+2] cycloaddition reaction between α,β-unsaturated aldehydes and α-ketophosphonates is developed. The reaction affords chiral 2-pyranylphosphonates with excellent enantioselectivities. The optically enriched phosphonate products bear multiple functional groups, including unsaturated lactone and phosphonate moieties that often lead to unique bio-activities. Preliminary studies show that the products from our reactions exhibit anti-bacterial (X. oryzae pv. oryzae) and anti-viral (Tobacco Mosaic Virus) activities for potential use in plant protection.
Copper(I)-Catalyzed Allylic Substitutions with a Hydride Nucleophile
Nguyen, T. N. Thanh,Thiel, Niklas O.,Pape, Felix,Teichert, Johannes F.
supporting information, p. 2455 - 2458 (2016/06/09)
An easily accessible copper(I)/N-heterocyclic carbene (NHC) complex enables a regioselective hydride transfer to allylic bromides, an allylic reduction. The resulting aryl- and alkyl-substituted branched α-olefins, which are valuable building blocks for synthesis, are obtained in good yields and regioselectivity. A commercially available silane, (TMSO)2Si(Me)H, is employed as hydride source. This protocol offers a unified alternative to the established metal-catalyzed allylic substitutions with carbon nucleophiles, as no adaption of the catalyst to the nature of the nucleophile is required.
Enantioselective Hydrogenation of β,β-Disubstituted Unsaturated Carboxylic Acids under Base-Free Conditions
Yan, Qiaozhi,Kong, Duanyang,Zhao, Wei,Zi, Guofu,Hou, Guohua
, p. 2070 - 2077 (2016/03/15)
An additive-free enantioselective hydrogenation of β,β-disubstituted unsaturated carboxylic acids catalyzed by the Rh-(R,R)-f-spiroPhos complex has been developed. Under mild conditions, a wide scope of β,β-disubstituted unsaturated carboxylic acids were hydrogenated to the corresponding chiral carboxylic acids with excellent enantioselectivities (up to 99.3% ee). This methodology was also successfully applied to the synthesis of the pharmaceutical molecule indatraline.
Green and Rapid Access to Benzocoumarins via Direct Benzene Construction through Base-Mediated Formal [4+2] Reaction and Air Oxidation
Mou, Chengli,Zhu, Tingshun,Zheng, Pengcheng,Yang, Song,Song, Bao-An,Chi, Yonggui Robin
supporting information, p. 707 - 712 (2016/03/09)
Benzocoumarin is an important structural motif widely found in natural products and synthetic molecules. Traditional methods for the synthesis of benzocoumarins and their derivatives require multiple steps, typically with an intramolecular ester forming reaction to make the lactone ring as the last step. Another major method involves transition metal-catalyzed coupling or carbon-hydrogen bond activation reactions starting with pre-existing aryl frameworks in the substrates. Here we report a new strategy for the green and rapid access to benzocoumarins and their derivatives. Our method uses readily available unsaturated aldehydes and coumarins as the substrates and air as the green oxidant. The overall reaction proceeds through a formal [4+2] process to construct a new benzene ring and thus to afford benzocoumarins in essentially a single step. No metal catalysts were used; no toxic or expensive reagents were involved. The power of our new approach is further demonstrated in a concise formal total synthesis of cannabinol, a bioactive natural product.
