Latest News:

10/31/14 - Congratulations to Kerem Ozboya for successfully defending his Ph.D. thesis. Kerem will be moving on to a post-doctoral fellowship position in the Nicewicz group.


09/22/14 - Congratulations to Jamie Neely for successfully defending her Ph.D. thesis. Jamie will will joining the Chirik group as a post-doctoral fellow.


06/7/2014 - Best of luck to Dr. Tyler Davis as he leaves to start his new position as a research scientist for GSK.

RECENT PUBLICATIONS:


Ligand design for Rh(III)-catalyzed C–H activation: an unsymmetrical cyclopentadienyl group enables a regioselective synthesis of dihydroisoquinolones

Todd K. Hyster, Derek M. Dalton, Tomislav Rovis

CHEMICAL SCIENCE (ASAP) (2014)

                                                    

We report the regioselective synthesis of dihydroisoquinolones from aliphatic alkenes and O-pivaloyl benzhydroxamic acids mediated by a Rh(III) precatalyst bearing sterically bulky substituents. While the prototypical Cp* ligand provides product with low selectivity, sterically bulky Cpt affords product with excellent regioselectivity for a range of benzhydroxamic acids and alkenes. Crystallographic evidence offers insight as to the source of the increased regioselectivity.


Enantioselective N-Heterocyclic Carbene-Catalyzed β-Hydroxylation of Enals Using Nitroarenes: An Atom Transfer Reaction That Proceeds via Single Electron Transfer

Nicholas A. White, Tomislav Rovis

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136, 14674-14677 (2014)

                                              

A novel oxidative N-heterocyclic carbene-catalyzed reaction pathway has been discovered. Alkyl and aryl enals undergo β-hydroxylation via oxygen atom transfer from electron-deficient nitrobenzenes, followed by trapping of the resultant acyl azolium by the solvent. The proposed mechanism involves a single electron transfer event to initiate the reaction followed by radical recombination. This represents a profound mechanistic departure from the established two-electron disconnects in NHC catalysis.

Rh(III)-Catalyzed Cyclopropanation Initiated by C–H Activation: Ligand Development Enables a Diastereoselective [2 + 1] Annulation of N-Enoxyphthalimides and Alkenes

Tiffany Piou, Tomislav Rovis

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136, 11292-11295 (2014)

                                           

N-Enoxyphthalimides undergo a Rh(III)-catalyzed C–H activation initiated cyclopropanation of electron deficient alkenes. The reaction is proposed to proceed via a directed activation of the olefinic C–H bond followed by two migratory insertions, first across the electron-deficient alkene and then by cyclization back onto the enol moiety. A newly designed isopropylcyclopentadienyl ligand drastically improves yield and diastereoselectivity.

Stereoelectronic Basis for the Kinetic Resolution of N-Heterocycles with Chiral Acylating Reagents

Sheng-Ying Hsieh, Benedikt Wanner, Philip Wheeler, André M. Beauchemin, Tomislav Rovis, Jeffrey W. Bode

CHEMISTRY - A EUROPEAN JOURNAL, 20, 7228-7231 (2014)

                                                             

The kinetic resolution of N-heterocycles with chiral acylating agents reveals a previously unrecognized stereoelectronic effect in amine acylation. Combined with a new achiral hydroxamate, this effect makes possible the resolution of various N-heterocycles by using easily prepared reagents. A transition-state model to rationalize the stereochemical outcome of this kinetic resolution is also proposed.

Cobaltate Anion Couples Terminal Dienes with Trifluoroacetic Anhydride: A Direct Fluoroacylation of 1,3-Diene

Benjamin L. Kohn, Tomislav Rovis

CHEMICAL SCIENCE, 5, 2889-2892 (2014)

                                                             

Perfluoroketones are useful products and intermediates in medicinal chemistry. Herein, cobalt-mediated fluoroacylation of 1,3-dienes is described using perfluorinated anhydrides such as TFAA. The reaction is thought to proceed through a fluoroacylcobalt reagent formed in situ. Perfluoroacylation of 1,3-dienes can also be performed to attain longer chain perfluorinated ketones.