Author
Jack L.-Y. Chen
Other affiliations: University of Auckland, University of Padua, MacDiarmid Institute for Advanced Materials and Nanotechnology ...read more
Bio: Jack L.-Y. Chen is an academic researcher from Auckland University of Technology. The author has contributed to research in topics: Total synthesis & Chemistry. The author has an hindex of 14, co-authored 30 publications receiving 666 citations. Previous affiliations of Jack L.-Y. Chen include University of Auckland & University of Padua.
Topics: Total synthesis, Chemistry, Dithiane, Amphiphile, Monolayer
Papers
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TL;DR: It is found that addition of nBuLi to the pinacol boronic ester followed by trapping of the alkoxide with TFAA leads to an intermediate allyl borinic ester which undergoes allylboration with very high E selectivity.
Abstract: Readily available, α-substituted allyl/crotyl pinacol boronic esters often give low E/Z selectivity (with Z favored) in reactions with aldehydes. We found that addition of nBuLi to the pinacol boronic ester followed by trapping of the alkoxide with TFAA leads to an intermediate allyl borinic ester which undergoes allylboration with very high E selectivity. The substrate scope includes primary to tertiary alkyl α-substituents, crotyl substrates, and the previously unreported β-methallyl pinacol boronic esters. The latter give very high Z selectivity under standard conditions which is completely reversed to high E selectivity under the new conditions. Monitoring the reaction by 11B NMR confirmed that the reaction proceeds through a borinic ester intermediate.
95 citations
TL;DR: 3,3-Disubstituted allylic boronic esters can be converted into the corresponding borinic esters by the sequential addition of nBuLi and TFAA, which allows the highly selective allylation of both ketones and ketimines, and facile access to adjacent quaternary stereocenters with full stereocontrol.
Abstract: 3,3-Disubstituted allylic boronic esters are not sufficiently reactive to react with ketones and imines. However, they can be converted into the corresponding borinic esters by the sequential addition of nBuLi and TFAA. These reactive intermediates possess the perfect balance between reactivity and configurational stability. Their enhanced reactivity allows the highly selective allylation of both ketones and ketimines, and facile access to adjacent quaternary stereocenters with full stereocontrol. The versatility of the methodology is demonstrated in the construction of all possible stereoisomers of a quaternary-quaternary motif and by the allylation of the heterocycles, dihydroisoquinoline and indole.
92 citations
TL;DR: This review focuses on synthetic molecular nanostructures which self-assemble under dissipative conditions and the chemical function associated with the transient assemblies is operational as long as chemical fuel is present.
72 citations
TL;DR: Asymmetric cross-coupling reactions in which stereo- chemistry-bearing CC bonds are created are still in their infancy, and advances in this area have occurred in the past few years, in the realm of enantioselective or enantiospecific cross- couplings of chiral electrophiles.
Abstract: Asymmetric cross-coupling reactions in which stereo- chemistry-bearing CC bonds are created are still in their infancy. Considering the wealth of compounds that can be prepared by cross-coupling methodologies, and the impor- tance of synthetic methods leading to enantiomerically en- riched products, this is a surprising reality. Advances in this area have occurred in the past few years, in the realm of enantioselective or enantiospecific cross-couplings of chiral electrophiles. (1) In the area of cross-coupling of stereodefined nucleo- philes, Crudden originally reported the enantiospecific cross-coupling of chiral enantiomerically enriched benzylic boronic esters (Eq. (1)). (2, 3)
64 citations
TL;DR: This review describes the use of monolayer protected gold nanoparticles (Au NPs) for chemosensing applications and shows that these systems are very well-equipped for metal ion sensing as the complexation of the metal ions can affect the properties of the system in many ways leading to detectable output signals even at very low analyte concentrations.
57 citations
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TL;DR: This review systematically introduces the classification, catalytic mechanism, activity regulation as well as recent research progress of nanozymes in the field of biosensing, environmental protection, and disease treatments, etc. in the past years.
Abstract: Because of the high catalytic activities and substrate specificity, natural enzymes have been widely used in industrial, medical, and biological fields, etc. Although promising, they often suffer from intrinsic shortcomings such as high cost, low operational stability, and difficulties of recycling. To overcome these shortcomings, researchers have been devoted to the exploration of artificial enzyme mimics for a long time. Since the discovery of ferromagnetic nanoparticles with intrinsic horseradish peroxidase-like activity in 2007, a large amount of studies on nanozymes have been constantly emerging in the next decade. Nanozymes are one kind of nanomaterials with enzymatic catalytic properties. Compared with natural enzymes, nanozymes have the advantages such as low cost, high stability and durability, which have been widely used in industrial, medical, and biological fields. A thorough understanding of the possible catalytic mechanisms will contribute to the development of novel and high-efficient nanozymes, and the rational regulations of the activities of nanozymes are of great significance. In this review, we systematically introduce the classification, catalytic mechanism, activity regulation as well as recent research progress of nanozymes in the field of biosensing, environmental protection, and disease treatments, etc. in the past years. We also propose the current challenges of nanozymes as well as their future research focus. We anticipate this review may be of significance for the field to understand the properties of nanozymes and the development of novel nanomaterials with enzyme mimicking activities.
1,549 citations
TL;DR: This work states that the stereocontrolled construction of C−C bonds remains one of the foremost challenges in organic synthesis and has resulted in a paradigm shift in synthetic strategy planning.
Abstract: The stereocontrolled construction of C−C bonds remains one of the foremost challenges in organic synthesis. At the heart of any chemical synthesis of a natural product or designed small molecule is the need to orchestrate a series of chemical reactions to prepare and functionalize a carbon framework. The advent of transition-metal catalysis has provided chemists with a broad range of new tools to forge C−C bonds and has resulted in a paradigm shift in synthetic strategy planning. The impact of these methods was recognized with the awarding of the 2010 Nobel Prize in Chemistry to Richard Heck, Ei-ichi Negishi, and Akira Suzuki for their seminal contributions to the development of Pd-catalyzed cross-coupling.
593 citations
TL;DR: This work focuses on the control of directional movement, both at the molecular scale and at larger magnitudes, and identifies some key challenges remaining in the field.
Abstract: Motor proteins are nature's solution for directing movement at the molecular level. The field of artificial molecular motors takes inspiration from these tiny but powerful machines. Although directional motion on the nanoscale performed by synthetic molecular machines is a relatively new development, significant advances have been made. In this review an overview is given of the principal designs of artificial molecular motors and their modes of operation. Although synthetic molecular motors have also found widespread application as (multistate) switches, we focus on the control of directional movement, both at the molecular scale and at larger magnitudes. We identify some key challenges remaining in the field.
591 citations
TL;DR: The integrative nanozymes of AuNPs were used to evaluate the therapeutic efficacy of potential drugs and determine glucose and lactate metabolism in tumors and provided an interesting approach to designing nanoZymes for biomedical and catalytic applications.
Abstract: Gold nanoparticles (AuNPs) with simultaneous plasmonic and biocatalytic properties provide a promising approach to developing versatile bioassays However, the combination of AuNPs’ intrinsic enzyme-mimicking properties with their surface-enhanced Raman scattering (SERS) activities has yet to be explored Here we designed a peroxidase-mimicking nanozyme by in situ growing AuNPs into a highly porous and thermally stable metal–organic framework called MIL-101 The obtained AuNPs@MIL-101 nanozymes acted as peroxidase mimics to oxidize Raman-inactive reporter leucomalachite green into the active malachite green (MG) with hydrogen peroxide and simultaneously as the SERS substrates to enhance the Raman signals of the as-produced MG We then assembled glucose oxidase (GOx) and lactate oxidase (LOx) onto AuNPs@MIL-101 to form AuNPs@MIL-101@GOx and AuNPs@MIL-101@LOx integrative nanozymes for in vitro detection of glucose and lactate via SERS Moreover, the integrative nanozymes were further explored for monitoring
453 citations
TL;DR: This feature article summarises the current state of the art in stereospecific transformations of both secondary and tertiary boronic esters into other functionalities and groups, whilst considering critically the transformations that are currently unattainable and would represent future advances to the field.
345 citations