Research in organic chemistry at UNC Chapel Hill covers a broad range of subjects from natural products synthesis to the study of organic free-radicals with time-resolved EPR spectroscopy. Research is often interdisciplinary and involves science at the frontiers of polymer chemistry, inorganic chemistry, physical chemistry, materials science and bioorganic chemistry. With nine faculty members formally in the organic division and a number of faculty members from other divisions whose research involves organic chemistry, graduate students find they have a wide range of choices for their doctoral research.
The efficient synthesis of highly substituted cyclopentanols is an important task given the prevalence of this class of compounds in nature. Nitrocyclopentanols are of particular value due to the rich chemistry associated with the nitro group and their potential use as aminocyclopentitol progenitors. Aminocyclopentitols have generated considerable attention because of their significant biological activity and synthetic challenges presented by their often dense functionality and contiguous chiral centers.
As such, the development of a flexible synthesis of functionalized nitrocyclopentanols would be a welcome addition to the synthetic toolbox. In an article published in Angewandte Chemie, Gregory Boyce and Jeffrey Johnson in the Johnson Group report the three-component coupling of silyl glyoxylates, CH2CHMgBr, and nitroalkenes that selectively affords (Z)-silyl enol ether products through a unique vinylogous Michael cascade. The resulting functionality enables the immediate implementation of a second-stage Henry cyclization for the expeditious, diastereoselective synthesis of functionalized nitrocyclopentanols.
Published in JACS, researchers in the Johnson Group discuss how Reformatsky reagents react sequentially with silyl glyoxylates and β-lactones to give highly functionalized Claisen condensation products. A heretofore undocumented instance of stereochemical 1,4-induction results in efficient transmission of β-lactone stereochemistry to the emerging fully substituted stereocenter.
Second-stage transformations reveal that the five heteroatom-containing functionalities embedded within the products are entirely chemo-differentiated, a circumstance that permits rapid assembly of the leustroducsin B core substructure.
Synthesis of Highly Substituted Tetrahydrofurans by Catalytic Polar-Radical-Crossover Cycloadditions of Alkenes and Alkenols. Jean-Marc M. Grandjean, David A. Nicewicz. Angewandte Chemie International Edition, Volume 52, Issue 14, pages 3967–3971, April 2, 2013.
Enantioselective Synthesis of Pactamycin, a Complex Antitumor Antibiotic. Justin T. Malinowski, Robert J. Sharpe, Jeffrey S. Johnson. Science 12 April 2013: Vol. 340 no. 6129 pp. 180-182.
Diametric Stereocontrol in Dynamic Catalytic Reduction of Racemic Acyl Phosphonates: Divergence from α-Keto Ester Congeners. Michael T. Corbett and Jeffrey S. Johnson. J. Am. Chem. Soc., 2013, 135 (2), pp 594–597.
Enantioselective Intermolecular [2 + 2 + 2] Cycloadditions of Ene–Allenes with Allenoates. Andrew T. Brusoe , Rahul V. Edwankar , and Erik J. Alexanian. Org. Lett., 2012, 14 (23), pp 6096–6099.
Catalytic Enantioselective Cyclization and C3-Fluorination of Polyenes. Nikki A. Cochrane, Ha Nguyen, and Michel R. Gagné. J. Am. Chem. Soc., 2013, 135 (2), pp 628–631.
Iridium-Catalyzed Hydrosilylative Reduction of Glucose to Hexane(s). Matthew P. McLaughlin, Laura L. Adduci, Jennifer J. Becker, and Michel R. Gagné. J. Am. Chem. Soc., Article ASAP, DOI: 10.1021/ja3110494.
Asymmetric Synthesis of Diverse Glycolic Acid Scaffolds via Dynamic Kinetic Resolution of α-Keto Esters. Kimberly M. Steward, Michael T. Corbett, C. Guy Goodman, and Jeffrey S. Johnson. J. Am. Chem. Soc., 2012, 134 (49), pp 20197–20206.
Cu(II)-Catalyzed Aerobic Hydroperoxidation of Meldrum's Acid Derivatives and Application in Intramolecular Oxidation: A Conceptual Blueprint for O2/H2 Dihydroxylation. Scott W. Krabbe, Dung T. Do, and Jeffrey S. Johnson. http://pubs.acs.org/doi/abs/10.1021/ol302848m.
Direct Catalytic Anti-Markovnikov Hydroetherification of Alkenols. David S. Hamilton and David A. Nicewicz. J. Am. Chem. Soc., Article ASAP, DOI:10.1021/ja309635w.
α-Amination of Keto-Nitrones via Multihetero-Cope Rearrangement Employing an Imidoyl Chloride Reagent. Justin Malinowski, Ericka Malow and Jeffrey Johnson. Chem. Commun., 2012,48, 7568-7570.