Chemical Catalysis

Novartis Lecture - Helen Blackwell, Wisconsin

Thu, 2013-04-25 14:00
Speaker: 

Prof. Helen Blackwell

University of Wisconsin, Madison

Location: 

Lynch Lecture Hall

Special Seminar: Erol Akçay, Princeton

Mon, 2013-02-04 10:00
Speaker: 
Dr. Erol Akçay
Princeton University

New frontiers in social evolution theory

Host: Josh Plotkin (Biology)
Location: 

Lynch Lecture Hall

 

Cooperation between organisms is a major driving force of biological organization at all levels, from single cells to whole ecosystems. Understanding the evolutionary dynamics of cooperation and other social traits therefore is a central goal of evolutionary theory. I will talk about my recent work that aims to advance the frontiers of social evolution theory in two directions.

 

Special Seminar: Emilia Huerta-Sanchez, University of California, Berkeley

Mon, 2013-01-28 10:00
Speaker: 

Dr. Emilia Huerta-Sanchez

University of California, Berkeley

 

Detecting and characterizing natural selection from next generation sequencing data

 

Host: Charles Epstein (Math)

Location: 

Lynch Lecture Hall

 

Special Seminar: Sharon Aviran, University of California, Berkeley

Thu, 2013-01-24 10:00
Speaker: 

Dr. Sharon Aviran

University of California, Berkeley

 

High-throughput RNA structure analysis from chemical footprinting experiments

 

Host: Randy Kamien (Physics)

Location: 

Lynch Lecture Hall

 

New regulatory roles continue to emerge for both natural and engineered RNAs, many of which have specific structures essential to their function. This highlights a growing need to develop technologies that enable rapid and accurate characterization of structural features within complex RNA populations. Yet, available techniques that are reliable are also vastly limited by technological constraints, while the accuracy of popular computational methods is generally poor. These limitations thus pose a major barrier to comprehensive determination of structure from sequence.

Special Seminar: Kirill Korolev, MIT

Tue, 2013-01-22 10:00
Speaker: 

Dr. Kirill Korolev

Massachusetts Institute of Chemistry

 

The interplay between ecology and evolution in cancerous tumors and expanding populations

 

Host: Andrea Liu

Location: 

Lynch Lecture Hall

 

Special Seminar: Eleni Katifori, MPI-Goettingen

Thu, 2013-01-17 10:00
Speaker: 

Dr. Eleni Katifori

Max Planck Institute - Goettingen

 

The evolution of leaf vasculature: deciphering the design of optimal loopy architectures

 

Host: Douglas Jerolmack (Earth and Environmental Sciences)

Location: 

Lynch Lecture Hall

 

2013 Edgar Fahs Smith Lecture - Josef Michl, Univ. of Colorado

Thu, 2013-03-14 18:00
Speaker: 

Josef Michl, University of Colorado

 

Singlet Fission for Solar Cells

Location: 

Carolyn Lynch Lecture Hall

Inaugural Aldrich Distinguished Lecture

Mon, 2012-10-15 16:00
Speaker: 

Stephen L. Buchwald
Camille Dreyfus Professor of Chemistry
Massachusetts Institute of Technology

Location: 

Carolyn Lynch Lecture Hall

Palladium-Catalyzed Carbon-Nitrogen and Carbon-Carbon Bond-Forming Reactions: Progress, Applications and Mechanistic Studies

Patrick J. Walsh

Photo: 
First Name: 
Patrick J.
Last Name: 
Walsh
Official Title: 
Professor of Chemistry

Inorganic Chemistry, Organic Chemistry, Chemical Catalysis

Contact Information
Office Location: 
3001 IAST
Email: 
pwalsh@sas.upenn.edu
Phone: 
(215) 573-2875
Fax: 
(215) 573-6743
Admin Support: 
Education: 
  • Advisor Prof. K. Barry Sharpless
  • 1986 B.A. in Chemistry, University of California, San Diego
  • 1991 Ph.D in Chemistry, University of California, Berkeley
  • 1991-1994 NSF Postdoctoral Fellow Postdoctoral, The Scripps Research Institute
Research Interests: 

Research in the Walsh group merges the fields of catalysis and organic and inorganic synthesis with the goal of achieving new catalytic and stoichiometric transformations.  

 

Current projects include:

 

Application of cation-pi interactions to facilitate activation of benzylic C–H bonds. This is exemplified by the arylation of toluene, where it was demonstrated that cation-pinteractions enable the deprotonation of toluene with relatively mild silyl amide bases (Scheme 1) and Cs+catalyzed aminobenzylation of aldehydes (Scheme 2).

 

The study of unusual reactivity has been an active area of recent research in the Walsh group.  These include the discovery of 2-azaallyl anions as super electron donors (SEDs).  In this chemistry, deprotonation of benzophenone ketimines generates 2-azaallyl anions (A0).  Traditionally, these species undergo two electron reactions, acting as nucleophiles.  We found that they can also undergo single electron transfer (SET) to the starting ketimine (Scheme 3) to generate a 2-azaallyl radical (A0) and a ketiminyl anion (A2).  As shown in Scheme 4, the 2-azaallyl radical can react with unactivated vinyl bromides to give vinylation products under transition metal free conditions.  The utility of this method was demonstrated in the synthesis of benzofuran derivatives (Scheme 5).  We have also found that 2-azaallyl anions react with [1.1.1]propellane to give bicyclo[1.1.1]pentane (BCPs) derived amines. The BCP group is a bioisosteres of the phenyl group, making these compounds BCP analogues of diarylmethyl amines, which are extremely important in pharmaceutical sciences (5 of the top 200 medications contain diarylmethyl amines).

 

 

Other reactive intermediates include the development of sulfenate anions [ArSO]–for dehydrocoupling of benzyl chlorides, the first catalytic synthesis of all three bonds of alkynes (see below). Application of these reactions to the synthesis of stilbene-based polymers, including novel PPVs, is an area of ongoing work.   For more information, see the research areas section of the group’s website!

 

Department of Chemistry

231 S. 34 Street, Philadelphia, PA 19104-6323

215.898.8317 voice | 215.573.2112 fax | web@chem.upenn.edu

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