Chiral iminophosphorane catalyzed asymmetric sulfenylation of 4-substituted pyrazolones
作者:Jianwei Han、Yanxia Zhang、Xin-Yan Wu、Henry N. C. Wong
DOI:10.1039/c8cc09049a
日期:——
An excellent level of enantioselectivity in asymmetric sulfenylation of 4-substituted pyrazolones was achieved with chiral iminophosphorane as the organocatalyst under continuum solvation conditions (up to 99% ee). Importantly, this catalytic process features high efficiency with excellent enantioselectivities, easy separation of products, low catalytic loadings and scale-up to grams without loss of
Pd-Catalyzed Asymmetric Allylic Alkylation of Pyrazol-5-ones with Allylic Alcohols: The Role of the Chiral Phosphoric Acid in C–O Bond Cleavage and Stereocontrol
作者:Zhong-Lin Tao、Wen-Quan Zhang、Dian-Feng Chen、Arafate Adele、Liu-Zhu Gong
DOI:10.1021/ja402740q
日期:2013.6.26
The combination of a palladium complex with a chiral phosphoramidite ligand and a chiral phosphoric acid enables the first highly efficient asymmetricallylic alkylation of pyrazol-5-ones with allylicalcohols, affording multiply functionalized heterocyclic products in high yields with excellent enantioselectivities that would be of great potential in the synthesis of pharmaceutically interesting molecules
A highly enantioselective regiodivergent addition of alkoxyallenes to pyrazolones was developed to afford multiply functionalized alkylated products bearing a quaternary carbon stereocenter in high yields with excellent stereoselectivities. One approach is enabled by palladiumcatalysis, thus leading to branched allylic pyrazol‐5‐ones under mild reaction conditions. The other is catalyzed by a chiral
Asymmetric Hydroxylation of 4-Substituted Pyrazolones Catalyzed by Natural <i>Cinchona</i>
Alkaloids
作者:Fuzhao Xue、Xiaoze Bao、Liwei Zou、Jingping Qu、Baomin Wang
DOI:10.1002/adsc.201601070
日期:2016.12.22
A natural quinine‐catalyzed, efficient and practical asymmetric α‐hydroxylation of 4‐substituted pyrazolones has been developed, delivering a broad spectrum of pyrazolones bearing an oxygen‐attached carbon stereocenter at C‐4 in high yields and excellent enantioselectivities. The broad substrate scope, ready availability of the catalyst, ease of operation, and valuable transformation of the product
Enantioselective Direct α-Arylation of Pyrazol-5-ones with 2-Indolylmethanols via Organo-Metal Cooperative Catalysis
作者:Zi-Qi Zhu、Yang Shen、Jin-Xi Liu、Ji-Yu Tao、Feng Shi
DOI:10.1021/acs.orglett.7b00351
日期:2017.4.7
The first catalytic asymmetric α-arylation of pyrazol-5-ones has been established by using 2-indolylmethanols as direct electrophilicarylation reagents under the cooperative catalysis of Pd(0) and a chiral phosphoric acid, which afforded the α-arylation products of pyrazol-5-ones in generally high yields and good enantioselectivities (up to 99% yield, >99% ee).