Enantioselective Synthesis of 3,4-Chromanediones via Asymmetric Rearrangement of 3-Allyloxyflavones
作者:Jean-Charles Marié、Yuan Xiong、Geanna K. Min、Adam R. Yeager、Tohru Taniguchi、Nina Berova、Scott E. Schaus、John A. Porco
DOI:10.1021/jo100889c
日期:2010.7.2
Asymmetric scandium(III)-catalyzed rearrangement of 3-allyloxyflavones was utilized to prepare chiral, nonracemic 3,4-chromanediones in high yields and enantioselectivities. These synthetic intermediates have been further elaborated to novel heterocyclic frameworks including angular pyrazines and dihydropyrazines. The absolute configuration of rearrangement products was initially determined by a nonempirical
Intermolecular Triazene Alkene Cycloaddition via Lewis Base Catalysis: Access to Diverse Trifluoromethylated Pyrazolines
作者:Shiyong Peng、Huijuan Zhu、Haiyun Wu、Di Hao、Liangliang Yang、Yangyang Liu、Xiaojie Gong、Jianhe Wei、Lei Wang
DOI:10.1002/chem.202300562
日期:2023.7.14
An efficient Lewis base catalytic transformation to functionalized 3- and 5-trifluoromethylpyrazolines is developed via [3+2] triazene-alkene cycloaddition reactions of an array of unactivated alkenes with CF3CHN2. This approach features good functional group tolerance and mild reaction conditions. Synthetic utility of the procedure is elucidated by structure diversification of known pharmaceuticals
Asymmetric catalytic [1,3]- or [3,3]-sigmatropic rearrangement of 3-allyloxy-4H-chromenones and their analogues
作者:Yi Li、Lichao Ning、Qi Tang、Kexin Lan、Bingqian Yang、Qianchi Lin、Xiaoming Feng、Xiaohua Liu
DOI:10.1039/d4sc02201g
日期:——
A highly efficient asymmetric [1,3]- and [3,3]-O-to-C sigmatropic rearrangement of 3-allyloxy-4H-chromenones and their analogues was developed. Chiral N,N′-dioxide complexes of 3d late transition metal complexes enabled two mechanistically different processes, giving a series of optically active 2,2-disubstituted chromane-3,4-diones and 2-allyl-3-hydroxy-4H-chromen-4-ones as well as their related compounds