Faculty

Ming-Yu NgaiMing-Yu Ngai, Assistant Professor

B.S. University of Hong Kong/UC San Diego
Ph.D. University of Texas, Austin

Croucher Foundation Post-doctoral Fellow, Stanford University, 2009-2011
Post-doctoral Associate, Harvard University, 2011-2013

Phone: (631) 632-2641
Email:

 

The Ngai Group Website

 

Research

The Ngai lab focuses on (i) developing novel and practical synthetic methodologies to address unmet challenges in organic synthesis and medicinal chemistry, and (ii) identifying and developing new radiotracers for Positron Emission Tomography (PET) imaging to elucidate disease mechanisms, identify drug targets, assess treatment efficacy, and accelerate drug discovery and development. Our research programs are multidisciplinary, covering organic and organometallic chemistry, photochemistry, radiochemistry, and biomedical imaging.

Bio-Inspired Catalysis for Organic Synthesis

C–C and C–heteroatom bond forming reactions are vital to a broad range of areas including fine chemicals, pharmaceuticals, and materials. Therefore, the development of new catalysts for general, efficient, practical, and stereoselective C–C and C–heteroatom bond forming reactions stands as a critical goal in chemical synthesis. Although a considerable number of existing synthetic methods aim toward such goals, processes that streamline organic synthesis, minimize byproduct waste, and maximize atom economy are highly desired. Enzymes catalyze numerous chemical transformations under ambient conditions. Such mild reaction conditions are made possible through multiple cooperative activations of substrates in enzyme active sites. Drawing inspiration from such activation modes, one of our research programs is directed toward designing and synthesizing easily assembled multifunctional catalysts to enable direct regio-, chemo-, diastereo-, and enantioselective conversion of C–H and/or C–OH to C–C and C–heteroatom with H2 or H2O as the only byproduct. In specific, we focus upon direct stereospecific alcohol activation through the use of bifunctional catalysts, which comprises a Lewis acidic component and a nucleophilic component. Our goal is to facilitate the direct catalytic conversion of chirally pure alcohols to various chiral C–heteroatom bonds with retention of stereochemistry and water as the only byproduct.

Visible-Light Photoredox Catalysis

Development of greener and milder reaction conditions for both known and new transformations poses a continuous challenge for synthetic organic chemists. Harvesting sunlight as an inexpensive, non-polluting, and abundant “reagent” for organic synthesis is very appealing. Although the first use of light as a renewable energy source for chemical reactions occurred more than a century ago, only recently has there been a surge of interest in applying visible light photoredox catalysis to organic transformations. This mode of catalysis relies on the general property that a photoredox catalyst has enhanced reducing and oxidizing power in its excited state as compared to its ground state. Our goal is to apply this general property to transition metal catalysis to enable new modes of chemical reactivity and unlock the potential of photoredox catalysis in organic chemistry. More specifically, we will merge photoredox catalysis with transition metal-mediated dearomatization reactions to enable catalytic dearomatization reactions and apply these transformations to the total synthesis of various cyclic natural products.

Positron Emission Tomography (PET) Tracers for the Study of Human Diseases

Chronic inflammation is a common feature of numerous severe human diseases, including cancer, diabetes, Alzheimer's disease, and various neurological disorders. Understanding the mechanisms that govern inflammation in tissues and diseases should provide new strategies for therapeutic intervention, and accelerate drug discovery and development. Glycogen synthase kinase 3 (GSK-3) is a key protein kinase regulating numerous cellular functions, which has been implicated in governing inflammatory processes. Our research program aims at developing GSK-3β imaging probes for positron emission tomography (PET), a non-invasive in vivo imaging technology using radioactive tracers to visualize, characterize, and quantify physiological processes at the cellular level. This in vivo imaging technology will enable researchers to directly study GSK-3β. Our ultimate goal is to translate this technology to human PET imaging to elucidate disease mechanisms, identify drug targets, assess treatment efficacy, and accelerate drug discovery and development.

Publications

“Ligand Accelerated Enantioselective Propargylation of Aldehydes via Allenylzinc Reagents” Trost, B. M.; Ngai, M.-Y.; Dong, G.-B. Org. Lett. 2011, 13, 1900.

“Enantioselective Iridium Catalyzed Carbonyl Allylation From the Alcohol or Aldehyde Oxidation Level via Transfer Hydrogenative Coupling of Allyl Acetate” Kim, I.-S.; Ngai, M.-Y.; Krische, M. J. J. Am. Chem. Soc. 2008, 130, 14891.

“Ruthenium Catalyzed C-C Bond Forming Transfer Hydrogenation: Reductive Coupling of Allenes to Paraformaldehyde and Higher Aldehydes” Ngai, M.-Y.; Skucas, E.; Krische, M. J. Org. Lett. 2008, 10, 2705.

“Enantioselective C-H Allylation of Alcohols Employing Allyl Acetate: Iridium Catalyzed Carbonyl Allylation from the Alcohol Oxidation Level” Kim, I.-S.; Ngai, M.-Y.; Krische, M. J. J. Am. Chem. Soc. 2008, 130, 6340.

“Enantioselective Iridium Catalyzed Imine Vinylation: Optically Enriched Allylic Amines via Alkyne-Imine Reductive Coupling Mediated by Hydrogen,” Ngai, M.-Y.; Barchuk, A.; Krische, M. J. J. Am. Chem. Soc. 2007, 129, 12644.

“Enantiomerically Enriched Allylic Alcohols and Allylic Amines via C-C Bond Forming Hydrogenation: Asymmetric Carbonyl and Imine Vinylation” Skucas, E.; Ngai, M.-Y.; Komanduri V.; .Krische, M. J. Acc. Chem. Res. 2007, 40, 1394.

“Allylic Amines via Iridium Catalyzed C-C Bond Forming Hydrogenation: Imine Vinlyation in the Absence of Stoichiometric Byproducts or Metallic Reagents” Barchuk, A.; Ngai, M.-Y.; Krische, M. J. J. Am. Chem. Soc. 2007, 129, 8432.

“Hydrogen-Mediated C-C Bond Formation: A Broad New Concept in Catalytic C-C Coupling” Ngai, M.-Y.; Kong, J.-R.; Krische, M. J. J. Org. Chem. 2007, 72, 1063.

“Iridium Catalyzed C-C Bond Forming Hydrogenation: Direct Regioselective Reductive Coupling of Alkyl-Substituted Alkynes to Activated Ketones” Ngai, M.-Y.; Barchuk, A.; Krische, M. J. J. Am. Chem. Soc. 2007, 129, 280.

“Lessons in Green Chemistry from the Smallest of Molecules: C-C Bond Formation via Catalytic Hydrogenation” Ngai, M.-Y.; Krische, M. J. Chim. Oggi/Chemistry Today 2006, 24, 12

“Highly Enantioselective Direct Reductive Coupling of Conjugated Alkynes and α-Ketoesters via Rhodium-Catalyzed Asymmetric Hydrogenation” Kong, J.-R.; Ngai, M.-Y.; Krische, M. J. J. Am. Chem. Soc. 2006, 128, 718.

“[(O^N^N)PtX] Complexes as a New Class of Light-Emitting Materials for Electrophosphorescent Devices” Kwok, C.-C.; Ngai, M.-Y.; Chan, S.-C.; Sham, I. H. T.; Che, C.-M.; Zhu, N. Inorg. Chem. 2005, 44, 4442.

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