The PI has recently discovered a method for the high precision combinatorial determination of small isotope effects at natural abundance. Compared to conventional methods for measuring isotope effects, the methodology is 1-2 orders of magnitude faster, is much more versatile, provides much greater information, and is more reliably accurate. Based on this discovery it is proposed here to study the mechanisms of a series of important organic and bioorganic reactions. These include the TMSCl-mediated addition of cuprates to enones, the Sharpless asymmetric dihydroxylation, ozonolysis, the enzymatic cyclization of squalene oxide, ene reactions and many others. The unique capabilities of the methodology should significantly advance mechanistic understanding of these reactions. The health-relatedness of this work derives from its impact on the understanding of reactions important in the synthesis of medicinally important substances, and reactions centrally important in biosynthetic pathways. Another objective is to extend the methodology to the determination of binding isotope effects. A detailed analysis of the impact of small isotope effects on chromatographic separations suggests that their ultra-high precision determination should be possible by NMR analysis after chromatographic separation. The precise isotope effects obtained should provide tremendous information on molecule-molecule or molecule-surface interactions. The goal is to develop practical methodology for the general study of binding isotope effects, and develop the use of this methodology in studying molecule-molecule binding interactions.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM045617-09
Application #
6018830
Study Section
Medicinal Chemistry Study Section (MCHA)
Project Start
1991-01-01
Project End
2000-06-30
Budget Start
1999-07-01
Budget End
2000-06-30
Support Year
9
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Texas A&M University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
047006379
City
College Station
State
TX
Country
United States
Zip Code
77845
Kurouchi, Hiroaki; Singleton, Daniel A (2018) Labelling and determination of the energy in reactive intermediates in solution enabled by energy-dependent reaction selectivity. Nat Chem 10:237-241
Bailey, Johnathan O; Singleton, Daniel A (2017) Failure and Redemption of Statistical and Nonstatistical Rate Theories in the Hydroboration of Alkenes. J Am Chem Soc 139:15710-15723
Issaian, Adena; Faizi, Darius J; Bailey, Johnathan O et al. (2017) Mechanistic Studies of Formal Thioboration Reactions of Alkynes. J Org Chem 82:8165-8178
Aziz, Hannah R; Singleton, Daniel A (2017) Concert along the Edge: Dynamics and the Nature of the Border between General and Specific Acid-Base Catalysis. J Am Chem Soc 139:5965-5972
Kurouchi, Hiroaki; Andujar-De Sanctis, Ivonne L; Singleton, Daniel A (2016) Controlling Selectivity by Controlling Energy Partitioning in a Thermal Reaction in Solution. J Am Chem Soc 138:14534-14537
Patel, Ashay; Chen, Zhuo; Yang, Zhongyue et al. (2016) Dynamically Complex [6+4] and [4+2] Cycloadditions in the Biosynthesis of Spinosyn A. J Am Chem Soc 138:3631-4
Nieves-Quinones, Yexenia; Singleton, Daniel A (2016) Dynamics and the Regiochemistry of Nitration of Toluene. J Am Chem Soc 138:15167-15176
Biswas, Bibaswan; Singleton, Daniel A (2015) Controlling Selectivity by Controlling the Path of Trajectories. J Am Chem Soc 137:14244-7
Plata, R Erik; Singleton, Daniel A (2015) A case study of the mechanism of alcohol-mediated Morita Baylis-Hillman reactions. The importance of experimental observations. J Am Chem Soc 137:3811-26
Andujar-De Sanctis, Ivonne L; Singleton, Daniel A (2012) Racing carbon atoms. Atomic motion reaction coordinates and structural effects on Newtonian kinetic isotope effects. Org Lett 14:5238-41

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