Dynamic Kinetic Resolution of Azlactones Catalyzed by Chiral Brønsted Acids
作者:Guojian Lu、Vladimir B. Birman
DOI:10.1021/ol102736t
日期:2011.2.4
Chiral Brønstedacids have been shown for the first time to catalyze the dynamic kineticresolution of azlactones. 3,3′-Bis-(9-anthryl)-BINOL phosphoric acid 3c is particularly effective in the case of 4-aryl-substituted substrates, producing 85−92% ee’s.
Catalytic Asymmetric [2+3] Cyclizations of Azlactones with Azonaphthalenes
作者:Chun Ma、Jia‐Yu Zhou、Yi‐Zhu Zhang、Guang‐Jian Mei、Feng Shi
DOI:10.1002/anie.201801349
日期:2018.5.4
The first catalyticasymmetric [2+3] cyclization of azlactones with azonaphthalenes has been established. This strategy allowed the synthesis of a variety of chiral isatin derivatives in generally good yields and excellent enantioselectivities (up to 99 % yield, 98 % ee). The developed reaction has not only established a catalytic enantioselective [2+3] cyclization using azlactones as two‐carbon building
The precise mechanism of the chiral phosphoric acid‐catalyzed aldol‐type reaction of azlactones with vinyl ethers was investigated. DFT calculations suggested that the reaction proceeds through a Conia‐ene‐type transition state consisting of the vinyl ether and the enol tautomer of the azlactone, in which the catalyst protonates the nitrogen atom of the azlactone to promote enol tautomerization. In
Organocatalytic regioselective asymmetric Michael addition of azlactones to o-hydroxy chalcone derivatives
作者:Shao-Yun Zhang、Gui-Yu Ruan、Zhi-Cong Geng、Nai-Kai Li、Ming Lv、Yong Wang、Xing-Wang Wang
DOI:10.1039/c5ob00121h
日期:——
enantioselective Michaeladdition between azlactones and o-hydroxy chalcone derivatives is reported. Enantiomerically enriched N,O-aminals with two continuous stereogenic centers are exclusively obtained in moderate to good yields with excellent diastereoselectivities and good to excellent enantioselectivities. The experimental results show that an o-hydroxy group on the cinnamenyl motif of chalcone derivatives