Zhihai Ke
@cuhk.edu.cn
School of Science and Engineering
The Chinese University of Hong Kong, Shenzhen
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Liangkun Pan, Ka-Mei Lee, Yung-Yin Chan, Zhihai Ke, and Ying-Yeung Yeung
American Chemical Society (ACS)
Non-symmetrical bromoiodanes are useful for bromination reactions, and some protocols were found to be suitable for specific substrates. Herein, we report the use of a DIB/BBr3 protocol for various bromination reactions, including electrophilic bromination of arenes, carbonyl C-H monobromination, bromolactonization, bromocarbocyclization, intermolecular bromoetherification of olefin, and light-triggered C(sp3)-H bromination.
Yanjie Wu, Yucheng Yang, and Zhihai Ke
American Chemical Society (ACS)
Graphdiyne (GDY) with a three-dimensional network structure was synthesized on a copper foam (CF) via an in situ Glaser-Hay coupling reaction. A metal-organic framework/GDY composite membrane was designed and synthesized for the first time. CF serves as a template and catalyst for the directed polymerization of GDY membranes. The catalytic activities of HKUST-1/GDY/CF membrane in wet peroxide oxidation of phenol, oxidation of benzyl alcohol, and ring opening of epoxide were studied. The composite membrane has the advantages of appropriateness for continuous operation, simple use process, easy recycling, high catalytic efficiency, etc. It was found that the incorporation of GDY can facilitate electron transfer and effectively improve the catalytic activity of HKUST-1 in membrane catalysis.
Liangkun Pan, Ka-Mei Lee, Zhihai Ke, and Ying-Yeung Yeung
Royal Society of Chemistry (RSC)
Efficient and metal-free cross-coupling of arenes has been developed. Inexpensive hypervalent iodine reagents (HIRs) diacetoxyl iodobenzene and BBr3 were used to in situ generate a non-symmetrical HIR as the active species.
Liangkun Pan, Long Zheng, Ye Chen, Zhihai Ke, and Ying‐Yeung Yeung
Wiley
A mechanochemical and solvent/catalyst-free functionalization of olefins with hypervalent iodine reagents has been developed, enabling the synthesis of 1,3-dioxygenated compounds. Under similar reaction conditions with the addition of molecular iodine, 1,4-iodoalcohols can be synthesized. These valuable products are non-trivial to achieve via standard solution-phase methods. Mechanistic study reveals that the hypervalent iodine reagent might dimerize at solid state with the help of mechanical force. The active monomeric form of hypervalent iodine reagent might trigger the 1,3- and 1,4-difunctionalization reactions in an intermolecular cascade manner.
Qingyu Zhang, Yung‐Yin Chan, Muyin Zhang, Ying‐Yeung Yeung, and Zhihai Ke
Wiley
A proof-of-concept study of hypervalent chalcogenonium···π bonding catalysis was performed. A new catalytic strategy using 1,2-oxaselenolium salts as chalcogen bond donors and alkenes as chalcogen bond acceptors is described. The feasibility of this concept is demonstrated by the use of trisubstituted selenonium salts in the metal-free catalytic hydrofunctionalization and polymerization of alkenes via unconventional seleniranium ion-like intermediates. The results indicate that counter anions have a significant effect on the catalysis based on hypervalent chalcogenonium···π bonding interactions.
Qingyu Zhang, Yongyuan Xu, Xiaochen Liang, and Zhihai Ke
Wiley
Brominated compounds are important, but they are usually prepared in organic solvents. We have developed efficient amphiphilic indole-based phase-transfer organocatalysts for environmentally benign bromination reactions in water. As test reactions, hydroxybromination of olefins and aromatic bromination can be conducted in a greener and more sustainable manner, producing the corresponding bromides in good yields. Some pure products can be obtained without column chromatography.
Chi-Hang Fan, Tianyue Xu, Zhihai Ke, and Ying-Yeung Yeung
Royal Society of Chemistry (RSC)
ipso-Hydroxylation of arylboronic acids with Hantzsch ester has been developed. The by-product Hantzsch pyridine was found to promote the reaction in the presence of oxygen under ambient conditions.
Liangkun Pan, Zhihai Ke, and Ying-Yeung Yeung
American Chemical Society (ACS)
1,2-Diols are extremely useful building blocks in organic synthesis. Hypervalent iodine reagents are useful for the vicinal dihydroxylation of olefins to give 1,2-diols under metal-free conditions, but strongly acidic promoters are often required. Herein, we report a catalytic vicinal dioxygenation of olefins with hypervalent iodine reagents using Lewis bases as catalysts. The conditions are mild and compatible with various functional groups.
Xinxin He, Xinyan Wang, Ying-Lung Steve Tse, Zhihai Ke, and Ying-Yeung Yeung
American Chemical Society (ACS)
Zhihai Ke and Ying-Yeung Yeung
Elsevier
Matthew H. Gieuw, Shuming Chen, Zhihai Ke, K. N. Houk, and Ying-Yeung Yeung
Royal Society of Chemistry (RSC)
Anti-Markovnikov hydrobromination of cyclopropanes was achieved using boron tribromide and water as the bromine and proton sources, respectively.
Zhihai Ke, Ying-Pong Lam, Kin-San Chan, and Ying-Yeung Yeung
American Chemical Society (ACS)
α,α-Dihalo-N-arylacetamides are commonly used as intermediates in various organic reactions. In the study described here, a catalytic synthesis of α,α-dihalo-N-arylacetamides from β-oxo amides was developed using zwitterionic catalysts and N-halosuccinimides as the halogen sources. The corresponding α,α-dihalo-N-arylacetamides were obtained in good to excellent yields, and no aromatic halogenated side products were detected. The reaction conditions were mild, and no strong base or acid was required.
Vincent Ming‐Yau Leung, Matthew H. Gieuw, Zhihai Ke, and Ying‐Yeung Yeung
Wiley
Jonathan Wong, Zhihai Ke, and Ying-Yeung Yeung
Elsevier BV
Zhihai Ke and Ying-Yeung Yeung
Elsevier BV
Yao Shi, Jonathan Wong, Zhihai Ke, and Ying-Yeung Yeung
American Chemical Society (ACS)
An environmentally benign and highly versatile catalytic protocol has been successfully applied in the intermolecular bromoesterification between various olefins and carboxylic acids. The use of a highly lipophilic indole catalyst and 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) as the bromine source allows the reaction to proceed in heptane via a solid-liquid phase transfer mechanism, affording the corresponding bromoester products in good-to-excellent yields.
Xiaojian Jiang, Haitao Wang, Haoquan He, Wei Wang, Yuqiang Wang, Zhihai Ke, and Ying-Yeung Yeung
Wiley
Matthew H. Gieuw, Vincent Ming-Yau Leung, Zhihai Ke, and Ying-Yeung Yeung
Wiley
Xinxin He, Xinyan Wang, Ying-Lung Steve Tse, Zhihai Ke, and Ying-Yeung Yeung
Wiley
The use of trisubstituted selenonium salts as organic Lewis acids in electrophilic halogenation and aldol-type reactions has been developed. The substrate scope is broad. The reaction conditions are mild and compatible with various functionalities. This study opens a new avenue for the development of nonmetallic Lewis acid catalysis.
Matthew H. Gieuw, Zhihai Ke, and Ying-Yeung Yeung
Wiley
A facile and effective system has been developed for the regio- and chemoselective ring-opening/electrophilic functionalization of cyclopropanes through C-C bond activation by [bis(trifluoroacetoxy)iodo]benzene with the aid of the Lewis basic promoter p-toluenesulfonamide. The p-toluenesulfonamide-promoted system works well for a wide range of cyclopropanes, resulting in the formation of 1,3-diol products in good yields and regioselectivity.
Jie Yang See, Hui Yang, Yu Zhao, Ming Wah Wong, Zhihai Ke, and Ying-Yeung Yeung
American Chemical Society (ACS)
Selenofunctionalization is used for the introduction of aryl- or alkylseleno moieties, which can then be transformed into other functional groups (such as alkenes and carbonyls). However, asymmetric selenofunctionalization of unactivated olefins is often difficult to realize, as aryl- and alkylseleno cations rapidly interchange between olefinic partners. Recently, it has been demonstrated that Lewis bases, assisted by Bronsted acids, induce high levels of enantioselectivity in selenocyclization reactions. The Bronsted acid serves as an activator for the reaction. In this work, we demonstrate an asymmetric selenoetherification and desymmetrization of olefinic 1,3-diols, driven by a unique chiral pairing between a C2-symmetric cyclic selenide catalyst and a chiral Bronsted acid. The resulting substituted tetrahydrofurans contain a phenylselenoether handle and can be transformed into synthetically useful building blocks. A series of experimental and computational investigations suggest that the reaction proc...
Zhihai Ke, Gavin Chit Tsui, Xiao-Shui Peng, and Ying-Yeung Yeung
Elsevier
Yao Shi, Zhihai Ke, and Ying-Yeung Yeung
Royal Society of Chemistry (RSC)
Position-selective halogenation of thioarenes and a wide range of aromatics using a highly lipophilic indole organocatalyst has been developed.
Matthew H. Gieuw, Zhihai Ke, and Ying-Yeung Yeung
Wiley
Oxygen- and nitrogen-containing heterocyclic compounds are widely recognized as key components in many natural products and biologically relevant molecules, but often the problem comes down to methodologies in synthesizing them. Halocyclization of olefinic substrates is a promising strategy in the construction of O- and N-heterocyclic compounds, which further signifies the development of their asymmetric variants. Over the past years, our group has been devoted to this particular area of asymmetric electrophilic halocyclization with chalcogen-containing molecules as catalysts. In this account, the main focus is on the development of our novel chiral catalysts and applications derived from the reaction products.