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Nucleophilic Substitution Reactions:
A Radical Alternative to SN1 and SN2 Reactions

 

Classical methods for achieving nucleophilic substitutions of akyl electrophiles (SN1 and SN2) have limited scope and are not generally amenable to enantioselective variants that employ readily available racemic electrophiles. In this presentation, I will describe how the combination of radical chemistry and transition-metal catalysis has opened the door to addressing the challenges of reactivity and of enantioselectivity in nucleophilic substitution reactions of secondary and tertiary alkyl electrophiles.

 


Professor Gregory C. Fu

Professor Gregory C. Fu 
Division of Chemistry and Chemical Engineering 
California Institute of Technology

Gregory C. Fu received a BS degree in 1985 from MIT, where he worked in the laboratory of Professor K. Barry Sharpless. After earning a PhD From Harvard in 1991 under the guidance of Professor David A. Evans, Fu spent two years as a postdoctoral fellow with the Victor and Elizabeth Atkins Professor of Chemistry Robert H. Grubbs at Caltech. In 1993, he returned to MIT, where he served as a member of the faculty from 1993-2012. In 2012, he was appointed the Altair Professor of Chemistry at Caltech. Fu is currently the Norman Chandler Professor of Chemistry at Caltech.

The current research interests of the Fu laboratory include metal-catalyzed coupling reactions and the design of chiral catalysts. In particular, the group is focused on the development of nickel-catalyzed enantioselective cross-couplings of alkyl electrophiles and on photoinduced, copper-catalyzed carbon-heteroatom bond-forming reactions (collaboration with the laboratory of Bren Professor of Chemistry Jonas Peters).

Fu received the Corey Award of the American Chemical Socioty (ACS) in 2004, the Mukaiyama Award of the Society of Synthetic Organic Chemistry of Japan in 2006, the Award for Creative Work in Synthetic Organic Chemistry of the ACS in 2012, and the H.C. Brown Award of the ACS in 2018. He is a member of the American Academy of Arts and Sciences (2007) and of the National Academy of Sciences (2014). Fu serves as an associate editor of the Journal of the American Chemical Society

 



Professor John J. Eisch

John Joseph Eisch joined the Department of Chemistry at Binghamton University in 1972, as chair and professor of chemistry, with the mandate of fostering the national reputation of its graduate teaching and research. Over the next six years as chair, he guided the recruiting of six senior and junior faculty with this goal in mind, while expanding his own research in organometallic chemistry to a yearly group of eight to 12 graduate and postdoctoral students, with support from federal and industrial resources. In 1983, his composite achievements were recognized by his promotion to the SUNY-wide rank of distinguished professor of chemistry. Further recruiting, notably during the chair tenure of professors Eugene Stevens, Alistair Lees, Wayne Jones and currently, Eriks Rozners, expanded the scope of advanced research into areas of immediate importance, such as nano materials, homogeneous catalysis, analytical sensors, biological transformations and energy storage.

Eisch received the BS degree in chemistry, summa cum laude, from Marquette University in 1952; earned the PhD degree in 1956, with Henry Gilman, at Iowa State University; and served as Union Carbide Research Fellow with Karl Ziegler at the Max-Planck-Institut für Kohlenforschung, Mülheim, Germany (1956–57).  After junior professional appointments at St. Louis University and the University of Michigan, he became ordinary professor and department head at the Catholic University of America (1963–1972). He retired from his professorial career of 57 years in 2014, the latter 42 years of which were spent at Binghamton University.

The Eisch Group initially had concentrated on the preparation and organic synthetic uses of organometallic reagents of Li, Na, Mg, B and Al, but we were struck by the lack of definitive molecular mechanistic studies in previous work. In ensuing research encompassing reaction kinetics, trapping of any intermediates, IR, UV and X-ray crystallographic measurements, both heterolytic and homolytic C-M cleavages could be involved, as well as 4-centertrapesoidal transition states. Reviews are available in a) “Fifty Years of Ziegler- Natta Polymerization: From Serendipity to Science,” Organometallics, 2012, 31, 4917–4932 and b) Dalton Transactions, (DOI: 10:1039/c4dt010362) “Emergence of Electrophilic Alumination as the Counterpart of Established Nucleophilic Lithiation.” The original seven articles dealing with the reactions of RLi with the azomethyne groups have been recently published by the Eisch and the Rheingold Crystallographic Group in the European Journal of Organic Chemistry.

Over the years, the research involved the fruitful collaboration of more than 200 students as master’s, doctoral, postdoctoral or baccalaureate associates. The results have been reported in more than 410 scientific publications, in some 280 invited lectures worldwide, in the monograph “The Chemistry of Organometallic Compounds” (Macmillian, 1967) and in the edited series, “Organometallic Syntheses” (four volumes, J. J. Eisch and R. B. King, authors and editors). He has been an industrial consultant on organometallic chemistry and an expert witness in several patent litigations on Ziegler-Natta polymerization catalysis.

 One of the significant discoveries of our studies is that the reaction of organic carbanionic reagents is not a one-step nucleophilic C alpha attack (i) but a two-step electrontransfer and electron-coupling process (ii)(iii).

reaction

Previous Lectureship Recipients

2012
Stephen L. Buchwald

MIT

“Palladium-Catalyzed CarbonNitrogen and Carbon-Carbon Bond-Forming Reactions: Progress, Applications and Mechanistic Studies”


2013
David W. C. MacMillan

Princeton University

“The Use of Photoredox Catalysis in New Organic Bond Forming Reactions”


2014
Brian M. Stoltz

California Institute of Technology

“Complex Natural Products as a Driving Force for Discovery in Organic Chemistry”


2015
Eric N. Jacobsen

Harvard University

“Anion-Binding Catalysis”


2016
Bob Crabtree

Yale University

“Organometallic Catalysis for Solar Fuels and Storage”

Phil S. Baran
The Scripps Research Institute

“Translational Chemistry”


2017
Stephen J. Lippard

MIT

“Understanding and Improving Platinum Anticancer Drugs”

Daniel A. Singleton
Texas A&M Uniersity

“Dynamic Effects and Energy Labeling in Free-Radical Reactions”


2018
Clifford P. Kubiak

University of California, San Diego

“If You Make a Solar Fuel From CO2, What Should It Be?”

Scott E. Denmark
University of Illinois at Urbana-Champaign

"Lewis-base Activation of Lewis Acids: An Evolving Paradigm for
Catalysis in Main Group Chemistry"

                                                                                  ________________________________________

2019

John F. Hartwig
University of California, Berkeley

"Selective, Catalytic Functionalization of C-H Bonds with Small and Large Catalysts"

Last Updated: 10/1/19