Wesley G. Bentrude
Professor (b. 1935)
Office: 3102 HEB
Department of Chemistry
University of Utah
Salt Lake City, UT 84112
Phone : (801) 581 - 7604
E-Mail : bentrude@chem.utah.edu
Field of Interest : Organic Chemistry
Wesley G. Bentrude
Professor (b. 1935)
Office: 3102 HEB
Department of Chemistry
University of Utah
Salt Lake City, UT 84112
Phone : (801) 581 - 7604
E-Mail : bentrude@chem.utah.edu
Field of Interest : Organic Chemistry
Research Interests
Current studies in our group involve several areas. Molecules such as I, that serve as models for the enzymatic hydrolysis of the important bioregulator molecule adenosine cyclic 3',5'-monophosphate (II), are being characterized structurally by NMR and X-ray crystallography. The kinetics of the intramolecular process that exchanges the positions of substituents on phosphorus are being related to structure. Additionally, the relationship of kinetic parameters to the factors that stabilize many of these phosphorus-containing rings in the twist/boat instead of the chair conformation, are being determined. Long range, these investigations of model systems may give insight to enzymologists trying to understand how cAMP interacts with protein kinases and key phosphodiesterases.
Unusual photochemical rearrangements discovered in our laboratory are being investigated from a mechanistic standpoint and also with regard to their applicability to synthesis. For example, the triplet excited states of allyl phosphites rearrange to allylphosphonates, presumably via the 1,3-biradical, III. The same overall rearrangement occurs when the excited singlet of 9,10-dicyanoanthracene accepts an electron from the pi bond or from the lone pair on phosphorus to yield a cation radical that cyclizes to presumed intermediate IV. These reactions are being employed in the synthesis of nucleoside-based phosphonates with potential antiviral or antitumor activity are underway.
Arylmethyl phosphites (V) photorearrange readily to VII. Mechanistic considerations of the potential intermediacy of free radical pairs (VI), their singlet or triplet multiplicity, and the stereochemistry at the carbon site of migration are of particular interest.
Very recently we have shown that vinyl radical (VIII) from cyclization of the 6-hexynyl radical
is trapped by (MeO)3P to yield vinylphosphonates (IX). The regiochemistry of this process and
its application to synthesis of phosphonates of biological and medicinal chemical interest are
under investigation.
Selected Publications
W. G. Bentrude, K. P. Dockery, S. Ganapathy, S.-G. Lee, M. Tabet, Y.-W. Wu, R. T. Cambron, J. M. Harris, "Triplet Sensitized Photorearrangements of 2-Phenylallyl Phosphites," J. Am. Chem. Soc. 118, 6192 (1996).
Y. Huang, W. G. Bentrude, "Conformational Equilibria of Phosphoranes with 5-Alkyl Substituted 1,3,2-Dioxaphosphorinane Rings Attached Diequatorially to Five-Coordinated Phosphorus. Are Boat/Twist Conformations Populated?" J. Am. Chem. Soc. 117, 12390 (1995).
S. Ganapathy, K.P. Dockery, A.E. Sopchik and W.G. Bentrude, "Photoinduced Single Electron Transfer Initiated Rearrangements of 2-Phenylallyl Phosphites," J. Am. Chem. Soc. 115, 8863 (1993).
Y. Huang, A.E. Sopchik, A.M. Arif and W.G. Bentrude, "NMR and X-ray Evidence for the Chair Conformation of Six-Membered Rings Attached Diequatorially to Five-Coordinate Phosphorus. Implications for Reported Transition State Analogs of Nucleoside Cyclic 3',5'-Monophosphate Hydrolysis", J. Am. Chem. Soc. 115, 4031 (1993).
K.B. Mullah, T. Sudhakar Rao, J. Balzarini, E. De Clercq and W.G. Bentrude, "Potential Prodrug Derivatives of 2',3'-Didehydro-2',3'-dideoxynucleosides. Preparation and Antiviral Activities," J. Med. Chem. 35, 2728 (1992).
J. H. Yu, A. M. Arif, and W. G. Bentrude, "Pentacovalent Phosphorus-Containing Models of
P(V) H2O- or Enzyme-cAMP Adducts. Non-chair Conformation of the Phosphorus-Containing
Rings as Determined by 1H NMR Spectroscopy and X-ray Crystallograph," J. Am. Chem. Soc.
112, 7451 (1990).
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