- Photoinduced Copper-Catalyzed Asymmetric C-O Cross-Coupling
-
The construction of carbon-heteroatom bonds is one of the most active areas of research in organic chemistry because the function of organic molecules is often derived from the presence of heteroatoms. Although considerable advances have recently been achieved in radical-involved catalytic asymmetric C-N bond formation, there has been little progress in the corresponding C-O bond-forming processes. Here, we describe a photoinduced copper-catalyzed cross-coupling of readily available oxime esters and 1,3-dienes to generate diversely substituted allylic esters with high regio- and enantioselectivity (>75 examples; up to 95% ee). The reaction proceeds at room temperature under excitation by purple light-emitting diodes (LEDs) and features the use of a single, earth-abundant copper-based chiral catalyst as both the photoredox catalyst for radical generation and the source of asymmetric induction in C-O coupling. Combined experimental and density functional theory (DFT) computational studies suggest the formation of π-allylcopper complexes from redox-active oxime esters as bifunctional reagents and 1,3-dienes through a radical-polar crossover process.
- Chen, Jun,Liang, Yu-Jie,Wang, Peng-Zi,Li, Guo-Qing,Zhang, Bin,Qian, Hao,Huan, Xiao-Die,Guan, Wei,Xiao, Wen-Jing,Chen, Jia-Rong
-
supporting information
p. 13382 - 13392
(2021/09/03)
-
- Photoinduced Palladium-Catalyzed Carbofunctionalization of Conjugated Dienes Proceeding via Radical-Polar Crossover Scenario: 1,2-Aminoalkylation and beyond
-
A photoinduced palladium-catalyzed 1,2-carbofunctionalization of conjugated dienes has been developed. This mild modular approach, which does not require employment of exogeneous photosensitizers and external oxidants, allows for efficient and highly regio- and stereoselective synthesis of a broad range of allylic amines from readily available 1,3-dienes, alkyl iodides, and amines. Employment of O- and C-nucleophiles toward oxyalkylation and dialkylation products was also demonstrated. A putative π-allyl palladium radical-polar crossover path is proposed as a key event in this three-component coupling process. The utility of this protocol is highlighted by its application for derivatization of several amine-containing drugs.
- Gevorgyan, Vladimir,Kurandina, Daria,Shing Cheung, Kelvin Pak,Yata, Tetsuji
-
supporting information
p. 9932 - 9937
(2020/06/27)
-
- Bioinspired intramolecular diels-alder reaction: A rapid access to the highly-strained cyclopropane-fused polycyclic skeleton
-
A bioinsipred gold-catalyzed tandem Diels-Alder/Diels-Alder reaction of an enynal and a 1,3-diene, forming the highly-strained benzotricyclo[3.2.1.0 2,7]octane skeleton, was reported. In contrast, a Diels-Alder/Friedel-Crafts tandem reaction occurred instead when silver salts were used as the catalyst. Although both reactions experienced the similar Diels-Alder reaction of a pyrylium intermediate with a 1,3-diene, they have different reaction mechanisms. The former proceeded with a stepwise Diels-Alder reaction, while the latter one with a concerted one. Mother nature knows best! A gold-catalyzed reaction of enynals and 1,3-dienes, giving rapid access to the highly strained benzotricyclo[3.2.1.02,7]octane skeleton, is reported (see scheme; QMD=quinodimethane). Owing to the mild reaction conditions, excellent substrate scope, and high functional-group tolerance, this system holds potential for the construction of complex molecules with the tricyclo[3.2.1.02,7]octane skeleton. Copyright
- Zhu, Shifa,Guo, Zhengjiang,Huang, Zhipeng,Jiang, Huanfeng
-
supporting information
p. 2425 - 2430
(2014/03/21)
-
- Design of 1,2-dioxines with anti-Candida activity: aromatic substituted 1,2-dioxines
-
In an ongoing effort to rationally design new antimicrobials, 47 new 1,2-dioxines have been synthesised. Broad antifungal structure-activity relationships governing aromatically substituted epoxy-1,2-dioxines 2 and 3 and their parent 1,2-dioxines 1 were a
- Macreadie, Ian G.,Avery, Thomas D.,Robinson, Tony V.,Macreadie, Peter,Barraclough, Miles,Taylor, Dennis K.,Tiekink, Edward R.T.
-
p. 1225 - 1232
(2008/09/17)
-