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Education:

• B.S. 1988 Chemistry & Math Calvin College
• M.S. 1990 Organic Chemistry University of Chicago
• Ph.D. 1994 Organic Chemistry University of Chicago
• Postdoctoral University of Chicago
• NIH Postdoctoral Columbia University

Overview

Richard P. Hsung went to Calvin College in Grand Rapids, MI, obtaining his B.S. in Chemistry and Mathematics in 1988, and worked on electrochemistry and micro-scale synthesis in Professors Ron Blankespoor and Ken Piers' laboratories. He attended The University of Chicago and received his M.S. and Ph.D. degrees in Organic Chemistry in 1990 and 1994, respectively, under supervisions of Professors Jeff Winkler and Bill Wulff. After pursuing post-doctoral research at Chicago with Professor Larry Sita in 1995, he completed his training as an NIH post-doctoral fellow in Professor Gilbert Stork's laboratory at Columbia University. In 1997, he moved to University of Minnesota as an Assistant Professor, was promoted to Associate Professor in 2002, and in 2006, moved to The Division of Pharmaceutical Sciences in School of Pharmacy at The University of Wisconsin-at Madison. The year 2004 was his best year because his dream of having the Boston Red Sox finally win the World Series came true while he was in China and he missed the entire Series.

Research

I. [4 + 3] Cycloaddition Chemistry of Allenamides We have been examining extensively the chemistry of 1-amidoallenes, or allenamides, and developed several major reactions associated with this new class of allenes. Most significantly, we achieved a tandem epoxidation and oxyallyl cation [4 + 3] cycloaddition using chiral allenamides. The epoxidation of allenamides proves to be an excellent source of chiral, nitrogen stabilized oxyallyl cations. We were able to develop highly regio- and stereoselective inter- and intramolecular oxyallyl cation [4 + 3] cycloadditions, and, very recently, we achieved the first asymmetric [4 + 3] cycloaddition using copper-bisoxazoline systems.

II. Stereoselective Methods Using Chiral Ynamides In a related but different area, we have developed the chemistry of ynamides as stable equivalents of Ficini's ynamines. Our work has rekindled the interest of the synthetic community toward this very interesting class of functional group. We have placed particular emphasis on developing a highly efficient synthesis of ynamides in order to provide the kind of accessibility that may allow the community to view ynamides as a user-friendly functional group in organic synthesis. Toward this goal, we developed a Cu(II)-catalyzed C-N bond formation involving sp-hybridized carbons. This catalytic amidation provides a direct entry to chiral ynamides via N-alkynylation of amides and should have an impact on the future synthetic utility.

III. Natural Product Total Syntheses We have developed a bio-inspired [3 + 3]-annulation reaction or formal cycloaddition of vinylogous amides or diketones with ±,²-unsaturated iminium salts that can be used to construct heterocycles]. The transformation involves a tandem Knoevenagel-6À-electron electrocyclic hetero ring-closure. This process has allowed us to achieve numerous total syntheses of complex natural products such as arisugacin A, tangutorine, hongoquercin A, perhydrohistrionicotoxin, cylindricines, and rhododaurichromanic acids.

IV. Ketal-Tethered Reactions and Natural Product Syntheses Ketal-tethered intramolecular reactions, specifically intramolecular Diels-Alder [IMDA] and RCM reactions, which are areas that have not been widely studied, are discussed here, as well as an approach to fusidilactone C and spirastrellolide A, spiroketal-containing natural products that first provoked our interest in ketal tethered strategies. These investigations are of significance because they can lead to conceptually and fundamentally different approaches to spiroketal-related complex natural products.

Highlighted Publications:

• "Thermal Intramolecular [4 + 2] Cycloadditions of Allenamides: A Stereoselective Tandem Propargyl Amide Isomerization?Cycloaddition."
  Lohse, A. G.; Hsung, R. P. Organic Lett. 2009, 11, 0000-0000.
• "Developing a Stereodivergent Approach Toward the C2-8a-Syn and Anti Stereochemical Mannifolds in the Lepadin Family via a TiCL4 Promoted Aza-[3 + 3] Annulation." [An Invited Special Topic]
  Li, G.; Sagamanova, I. K.; Carlson, L. J.; Hsung, R. P.; Slafer, B. W.; Sklenicka, H. M., Sydorenko, N.; Gilardi, C. Synthesis 2009, 0000-0000.
• "Synthesis of Amido-Spiro[2.2]Pentanes via Simmons-Smith Cyclopropanation of Allenamides."
  Lu, T.; Hayashi, R.; Hsung, R. P.; DeKorver, K. A.; Lohse, A. G.; Song, Z.; Tang, Y. Organic Biomol. Chem. 2009, 9, 0000-0000. [Hot Paper].
• "Regio- and Stereoselective Isomerization of Allenamides: Synthesis of 2-Amido-Dienes and Their Tandem Isomerization-Pericyclic Ring-Closure."
  Hayashi, R.; Hsung, R. P.; Feltenberger, J. B.; Lohse, A. G. Organic Lett. 2009, 11, 2125-2128.
• "A Rhodium(I)-Xylyl BINAP Catalyzed Asymmetric Ynamide-[2 + 2 + 2] Cycloaddition in the Synthesis of Optically Enriched N,O-Biaryls."
  Oppenheimer, J.; Johnson, W. L.; Figueroa, R.; Hayashi, R.; Hsung, R. P. Tetrahedron 2009, 64, 5001-5012.
• "Total Synthesis of Phomactin A."
  Tang, Y.; Cole, K. P.; Buchanan, G. S.; Li, G.; Hsung, R. P. Organic Lett. 2009, 11, 1591-1594.
• "Synthesis of Amidines Using N-Allyl Ynamides. A Palladium-Catalyzed Allyl Transfer via an Ynamido-p-Allyl Complex. "
  Zhang, Y.; DeKorver, K. A.; Lohse, A. G.; Zhang, Y.-S.; Huang, J.; Hsung, R. P. Organic Lett. 2009, 11, 899-902.
• "A General Approach to the Quinolizidine Family of Alkaloids via an Intramolecular Aza-[3 + 3] Annulation. Synthesis of (±)-2-Deoxy-Lasubine II."
  Zhang, Y.; Long, Q. A.; Gerasyuto, A. I.; Hsung, R. P. Synlett 2009, 237-240.
• "Challenges in the Synthesis of a Unique Mono-carboxylic Acid Antibiotic (+)-Zincophorin."
  Song, Z.; Lohse, A. G.; Hsung, R. P. Nat. Prod. Rept. 2009, 26, 560-571.
• "Total Synthesis of (+)-Lepadin F."
  Li, G.; Hsung, R. P.; Slafer, B. W.; Sagamanova, I. K. Organic Lett. 2008, 10, 4991-4994.
• "Synthesis of a-Keto-Imides via Oxidation of Ynamides."
  Al-Rashid, Z. F.; Johnson, W. L.; Hsung, R. P.; Wei, Y.; Yao, P.-Y.; Liu, R.; Zhao, K. J. Org. Chem. 2008, 73, 8780-8784.
• "Saucy-Marbet Rearrangements of Alkynyl Halides in the Synthesis of Highly Enantiomerically Enriched Allenyl Halides."
  Tang, Y.; Shen, L.; Dellaria, B. J.; Hsung, R. P. Tetrahedron Lett. 2008, 49, 6404-6409.
• "A Sequential Metal-Catalyzed C-N Bond Formation in the Synthesis of 2-Amido-Indoles."
  Yao, P.-Y.; Zhang, Y.; Hsung, R. P.; Zhao, K. Organic Lett. 2008, 10, 4275-4278.
• "A Highly Stereoselective Synthesis of Chiral a-Amino-b-Lactams via the Kinugasa Reaction Employing Ynamides."
  Zhang, X.; Hsung, R. P.; Li, H.; Zhang, Y.; Johnson, W. L.; Figueroa, R. Organic Lett. 2008, 10, 3477-3479.
• "Synthesis of the C1-C23 Fragment of Spirastrellolide A."
  Yang, J.; Liu, J.; Hsung, R. P. Organic Lett. 2008, 10, 2525-2528.
• "Gassman's Intramolecular [2 + 2] Cationic Cycloaddition. Formal Total Syntheses of Raikovenal and Epi-Raikovenal."
  Ko, C.; Feltenberger, J. B.; Ghosh, S. K.; Hsung, R. P. Organic Lett. 2008, 10, 1971-1974.
• "Reactive Intermediates from DMDO-Oxidation of Ynamides. Trapping of a De Novo Chiral Push-Pull Carbene via Cyclopropanation."
  Al-Rashid, Z. F.; Hsung, R. P. Organic Lett. 2008, 10, 661-663.
• "A Mutually pi-Facial Selective Cyclopropanation of Chiral Enamides Using Dirhodium(II) Carbenoids."
  Lu, T.; Song, Z.; Hsung, R. P. Organic Lett. 2008, 10, 541-544.
• "An Unexpected Reversal of Diastereoselectivity in the [4 + 3] Cycloaddition reaction of Nitrogen-Stabilized Chiral Oxyallyl Cations with 2-Furoates."
  Antoline, J. E.; Hsung, R. P. Synlett 2008, 739-744. [An Invited Article for the Cluster Communications on "Chemistry of Allenes and Alkynes." Hisashi Yamamoto, Ed.]
• "Aza- and Carbo-[3 + 3] Annulations of Exo-Cyclic Vinylogous Amides and Urethanes. Synthesis of Tetrahydroindolizidines and An Unexpected Formation of Hexahydroquinolines."
  Ghosh, S. K.; Buchanan, G. S.; Long, Q. A.; Wei, Y.; Al-Rashid, Z. F.; Sklenicka, H. M.; Hsung, R. P. Tetrahedron 2008, 63, 883-893. [An Invited Article for Tetrahedron-Symposium-In-Print on the Cycloaddition and Benzannulation Approaches to Functionalized Aromatic Compounds.]
• "Organic Synthesis Using 2-Oxazolidinone, 3-(1,2-propadienyl)." [An Invited Chapter-e8] Lu, T.; Hsung, R. P., in Encyclopedia of Reagents for Organic Synthesis, L. A. Paquette, Ed. John Wiley and Sons LTD, England, 2008.