748149-61-3Relevant articles and documents
Trans-4-Hydroxy-l-prolinamide as an efficient catalyst for direct asymmetric aldol reaction of acetone with isatins
Yadav, Geeta Devi,Singh, Surendra
, p. 463 - 466 (2016)
Prolinamide (2S,4R)-4-hydroxy-N-((S)-1-phenylethyl)pyrrolidine-2-carboxamide was found to be an efficient organocatalyst (10 mol %) for the direct asymmetric aldol reactions of isatins with acetone at -35 °C in THF and afforded the product in 79% yield wi
Asymmetric Three-Component Reaction for the Synthesis of Tetrasubstituted Allenoates via Allenoate-Copper Intermediates
Tang, Yu,Xu, Jian,Yang, Jian,Lin, Lili,Feng, Xiaoming,Liu, Xiaohua
supporting information, p. 1658 - 1672 (2018/05/16)
We developed an efficient and direct route for the synthesis of tetrasubstituted allenes via asymmetric multicomponent reaction (AMCR) by utilizing a variety of α-diazoesters, terminal alkynes, and isatins. This method enables Cu(I)-involved AMCRs of α-diazo compounds and also gives solid experimental evidence for the formation of allenoate-Cu(I) intermediates in C–H insertion of α-diazoesters to terminal alkynes. Combined-acid systems of guanidinylated metal complexes lead to higher reactivity and equally effective asymmetric environment. A catalytic asymmetric three-component reaction of α-diazoesters with terminal alkynes and isatins was achieved. This one-pot synthesis gave rise to axially chiral tetrasubstituted allenoates bearing a stereogenic center. The chiral guanidinium salt/CuBr/YBr3 catalytic system proved efficient and highly diastereo- and enantioselective for a wide range of alkynes, aromatic α-diazoesters, and isatins under mild reaction conditions. This approach enables a Cu(I)-involved asymmetric multicomponent reaction (AMCR) of α-diazo compounds and gives solid experimental evidence for the formation of allenoate-Cu(I) intermediates in C–H insertion of α-diazoesters to terminal alkynes. We also found that additional acids improved the catalyst efficiency of guanidinium salt/CuCl in the direct enantioselective C–H insertion of α-aryl diazoesters. Mechanism studies suggest that the combined-acid systems (Lewis acid combined with assisted Lewis acid or Br?nsted acid combined with assisted Lewis acid) bring out higher reactivity by associative interaction and allow for an equally effective asymmetric environment. Chirality is a universal phenomenon found in nature. Different from the usual central chirality, allenes are a class of compounds bearing three-carbon axially chiral skeletons and have attracted increasing attention for their usefulness as synthetic intermediates. This unique structural feature can provide allenes with specific biological activity and has been found in many drug molecules and natural products; thus, there is increasing demand for new routes toward these pharmaceutically relevant compounds. Nevertheless, the catalytic asymmetric synthesis of axially chiral allenes, especially for tetrasubstituted ones, is still in its infancy. Here, we report the synthesis of tetrasubstituted allenoates via an asymmetric three-component reaction of α-diazoesters with terminal alkynes and isatins. This gives access to the desired central and axial chirality bearing carbinol allenoate by trapping the corresponding allenoate-copper intermediate with isatin.
Asymmetric synthesis of cis-4-aminobenzopyran derivatives catalyzed by N,N′-Dioxide-Sc(OTf)3 complexes
Zhang, Yulong,Dong, Shunxi,Liu, Xiaohua,Xie, Mingsheng,Zhu, Yin,Lin, Lili,Feng, Xiaoming
supporting information; experimental part, p. 13684 - 13687 (2012/02/01)
The reactions of salicylaldimines with electron-rich alkenes (2,3-dihydro-2H-furan and 3,4-dihydro-2H-pyran) catalyzed by N,N′-dioxide-Sc(OTf)3 complexes were investigated. The methodology was successfully applied to the asymmetric synthesis of
