Babak Borhan

Synthetic and Bioorganic Chemistry


Professor

527 CEM

517-353-0501


Director of Admissions for the Graduate Program


Research webpage


Primary Research Area

Organic (Or)

Other Area(s) of Interest

Biological (Bi)

Research

The research interests of our lab can be subdivided into the three main areas of Bioorganic Chemistry, Synthetic Chemistry, and Organic Spectroscopy.

Our Bioorganic Chemistry  efforts are geared towards elucidation of the interaction of bioactive compounds with receptors and proteins. We rely heavily on de novo protein design and mimicry of natural systems to better understand how certain biological processes occur. As an example, we have initiated research into designing protein mimics of rhodopsin, the protein responsible for vision, which can bind retinal as a protonated Schiff base [PSB] (same binding mode as in rhodopsin). These protein mimics are used to investigate the wavelength regulation mechanism that enables color vision. Currently we are exploring the potential to use our engineered proteins as colorimetric and fluorescent proteins for cellular tagging and intracellular pH sensors.

Our Synthetic Chemistry program is generally focused on the development of new reactions that utilize simple organic molecules and through designed manipulations lead to more complex systems. In most cases, our methodologies lead to the production of heterocycles with regio- and stereocontrol. These transformations are then highlighted in total syntheses of natural products that exhibit interesting biological activities. Recently we have reported the catalytic asymmetric chlorolactonization of alkenoic acids and unsaturated amides to furnish chiral heterocycles. These reactions are catalyzed by (DHQD)2PHAL in combination with various N-chlorinated hydantoins as the terminal chlorenium sources. Halofunctionalization of different compounds, understanding the mechanism of these transformations and the details of enantioselections are currently under investigation.

In the area of Organic Spectroscopy, we are interested in developing host/guest systems that can be used in the absolute stereochemical determination of chiral compounds. We accomplish this through the design and synthesis of chromophoric receptors, which upon binding with the chiral compound function as reporters of chirality. We rely heavily on Circular Dichroism (CD) as the tool for observing the host/guest interactions between the chiral compounds and the receptors. In particular, we will take advantage of the excitonic coupling between independently conjugated chromo­­phores that make up the receptors to establish non-empirical guidelines for the absolute stereochemical determination of asymmetric centers.

Selected Publications

Nosrati, M.; Berbasova, T.; Vasileiou, C.; Borhan, B.; Geiger, J. H. "A Photoisomerizing Rhodopsin Mimic Observed at Atomic Resolution", J. Am. Chem. Soc. 2016, 138(28), 81802-8808.

Ashtekar, K.D.; Vetticatt, M.; Yousefi, R.; Jackson, J. E.; Borhan, B. "Nucleophile-Assisted Alkene Activation: Olefins Alone are Often Incompetent, J. Am. Chem. Soc. 2016, 138(26), 8114-8119.

Soltanzadeh, B.; Jaganathan, A.; Staples, R. J; Borhan, B. "Highly Stereoselective Intermolecular Haloetherification and Haloesterification of Allyl Amide", Angew. Chem. Int. Ed. Engl. 2015, 54, 9517-9522.

Tanasova, M.; Anyika, M.; Borhan, B. "Sensing Remote Chirality: Stereochemical Determination of beta-, gamma-, and delta-Chiral Carboxylic Acids", Angew. Chem. Int. Ed. Engl. 2015, 54, 4274-4278.

Yapici, I.; Lee, K. S. S.; Berbasova, T.; Nosrati. M.; Jia, X.; Vasileiou, C.; Santos, E. M.; Geiger, J. H.; Borhan, B. ""Turn-On" Protein Fluorescence: In Situ Formation of Cyanine Dyes", J. Am. Chem. Soc. 2015, 137, 1073-1080.

Ashtekar, K. D.; Marzijarani Salehi, N.; Jaganathan, A.; Holmes, D.; Jackson, J. E.; Borhan, B. "A New Tool to Guide Halofunctionalization reactions: The Halenium Affinityu (HalA) Scale", J. Am. Chem. Soc. 2014, 136, 13355-13362.

Anyika, M.; Gholami, H.; Ashtekar, K. D.; Acho, R.; Borhan, B. "Point-to-Axial Chirality Transfer—A New Probe for "Sensing" the Absolute Configurations of Monoamines", J. Am. Chem. Soc. 2014, 136, 550-553.

Berbasova, T.; Nosrati, M.; Vasileiou, C.; Wang, W.; Lee, K. S. S.; Yapici, I.; Borhan, B. "Rational Design of a Colorimetric pH Sensor from a Soluble Retinoic Acid Chaperone", J. Am. Chem. Soc. 2013, 135, 16111-16119.

Yousefi, R.; Ashtekar, K. D.; Whitehead, D. C.; Jackson, J. E.; Borhan, B."Dissecting the Stereocontrol Elements of a Catalytic Asummetric Chlorolactonization: Syn Addition Obviates Bridging Chloronium", J. Am. Chem. Soc. 2013, 135, 14524-14527.

Jaganathan, A.; Staples, R. J.; Borhan, B. "Kinetic Resolution of Unsaturated Amides in a Chlorocyclization Reaction: Concomitant Enantiomer Differentiation and Face Selective Alkene Chlorination by a Single Catalyst", J. Am. Chem. Soc. 2013, 135, 14806-14813.

Wang, W.; Nossoni, Z.; Berbasova, T.; Watson, C. T.; Yapici, I.; Lee, K. S. S.; Vasileiou, C.; Geiger, J. H.; Borhan, B. "Tuning the Electronic Absorption of Protein-Embedded All-trans-Retinal", Science, 2012, 338, 1340-1343.

CV

B.S., 1988, Univ. of California, Davis

Ph.D., 1995, Univ. of California, Davis

Postdoctoral Fellow, 1995-1998, Columbia Univ.

Awards/Honors

2015 Meritorious Faculty Award College of Natual Science
2004 Teacher-Scholar Award Michigan State University (College of Natural Science)
2002 University Teacher-Scholar Award Michigan State University
1995 Ph.D. University of California, Davis
1995 - 1998 Postdoctoral Fellow Columbia University
1994 Outstanding Teaching Assistantship Award University of California, Davis
1990 - 1993 Full foreign tuition fellowship University of California, Davis
1989 Bradford Borges Graduate Scholarship
1988 Bachelor of Science University of California, Davis
1987 - 1988 University of California Regents Scholarship University of California, Davis
1985 - 1986 University of California Undergraduate Scholarship University of California, Davis
Member Sigma Xi Honor Society (Michigan State University)