Kinetic Resolution and Dynamic Kinetic Resolution of Chromene by Rhodium-Catalyzed Asymmetric Hydroarylation
A highly efficient kinetic resolution and dynamic kinetic resolution of chromene is reported for the first time and they procced by a rhodium-catalyzed asymmetric hydroarylation pathway. This new approach offers versatile access to various chiral 2,3-diaryl-chromanes containing vicinal stereogenic centers, as well as the recovered chiral flavenes, in high yields with excellent ee values (s factor up to 532). Particularly noteworthy is that this strategy can be further extended to the establishment of a dynamic version of the kinetic resolution of chromene acetals and allows complete access to chiral isoflavanes and α-aryl hydrocoumarins.
Yang, Qingjing,Wang, Yanbo,Luo, Shihui,Wang, Jun (Joelle)
supporting information
p. 5343 - 5347
(2019/03/21)
Organocatalytic asymmetric Michael/hemiacetalization/acyl transfer reaction of α-nitroketones with o-hydroxycinnamaldehydes: Synthesis of 2,4-disubstituted chromans
An organocatalytic asymmetric cascade Michael/hemiketalization/acyl transfer reaction between o-hydroxycinnamaldehydes and α-nitroketones is developed. Prolinol TMS ether catalyst in combination with benzoic acid was found to be the most effective for this reaction which proceeds through an equilibrium of lactols to provide a single diastereomer of enantiopure 2,4-disubstituted chromans.
Maity, Rajendra,Pan, Subhas Chandra
supporting information
p. 1598 - 1608
(2018/03/08)
Bi(OTf)3-catalyzed addition of isocyanides to 2: H -chromene acetals: An efficient pathway for accessing 2-carboxamide-2 H -chromenes
Bismuth triflate (Bi(OTf)3) is identified as an efficient catalyst for the direct addition of isocyanides to 2H-chromene acetals. The large scope of isocyanides and chromene acetals makes them suitable substrates in this catalytic system. By this synthetic strategy, a polyfunctional molecular scaffold, 2-carboxamide-2H-chromenes could be prepared efficiently in one step up to 95% yield. In addition, this efficient and practical protocol proceeded smoothly in the gram scale even when the catalytic loading was reduced to 2 mol%.
Lyu, Longyun,Jin, Ming Yu,He, Qijie,Xie, Han,Bian, Zhaoxiang,Wang, Jun
supporting information
p. 8088 - 8091
(2016/09/09)
An efficient carbene-catalyzed access to 3,4-dihydrocoumarins
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Zeitler, Kirsten,Rose, Christopher A.
supporting information; experimental part
p. 1759 - 1762
(2009/08/07)
INTRAMOLECULAR CYCLIZATION OF 2-HYDROXYCINNAMALDEHYDES
The effect of substituents on the intramolecular cyclization of 2-hydroxycinnamaldehydes was studied.It was established that aldehydes that contain bulky groups in the side chain and in the 3 position of the benzene ring are readily converted to intramole
Chunaev, Yu. M.,Przhiyalgovskaya, N. M.,Kurkovskaya, L. N.
p. 376 - 381
(2007/10/02)
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