Latest News:

06/13/2013 - Congratulations to Dr. Todd Hyster for successfully defending his Ph. D. thesis. Todd will join Prof. Frances Arnold’s group at CalTech for a postdoc.


05/22/2013 - Congratulations to  Dr. Derek Dalton for successfully defending his Ph. D. thesis. Derek is off to UC-Berkeley for a Postdoc with Professor F. Dean Toste.


02/25/2013 - Dr. Tiffany Piou has joined our group as a post-doctoral fellow from the EPFL where she worked for Jieping Zhu.

RECENT PUBLICATIONS:


Rhodium(III)-Catalyzed Intramolecular Hydroarylation, Amidoarylation, and Heck-type Reaction: Three Distinct Pathways Determined by an Amide Directing Group

Tyler A. Davis, Todd K. Hyster, Tomislav Rovis

ANGEWANDTE CHEMIE INTERNATIONAL EDITION, 52, ASAP (2013)



The amide decides: Three different rhodium(III)-catalyzed reaction pathways of a wide variety of tethered alkenes can be accessed through changing the amide directing group. This provides an efficient route to a myriad of complex polycyclic products, many containing newly formed all-carbon quaternary centers. Amidoarylations can diastereoselectively deliver products with up to three contiguous stereocenters.


Rhodium(III)-Catalyzed C-H Activation Mediated Synthesis of Isoquinolones from Amides and Cyclopropenes

Todd K. Hyster, Tomislav Rovis

SYNLETT, 24, 1842-1844 (2013)




We have developed a synthesis of 4-substituted isoquinolones from the rhodium(III)-catalyzed, C–H activation mediated coupling of O-pivaloyl benzhydroxamic acids and 3,3-disubstituted cyclopropenes. Experiments suggest the formation of a [4.1.0] bicyclic system, which can open under acidic conditions to generate the desired isoquinolone.

SNAr-Derived Decomposition By-products Involving Pentafluorophenyl Triazolium Carbenes

Xiaodan Zhao, Garrett S. Glover, Kevin M. Oberg, Derek M. Dalton, Tomislav Rovis

SYNLETT, 24, 1229-1232 (2013)




Pentafluorophenyl triazolium carbenes, widely used in NHC catalysis, can decompose by several mechanisms. Under high concentration conditions, the azolium may undergo a pentafluorophenyl exchange by a proposed SNAr mechanism to give an inactive salt. In the presence of appropriate substrates, cyclization on the ­ortho-position of the arene can occur, also by SNAr. These adducts provide a potential pathway for catalyst decomposition and serve as a caveat to the development of new reactions and catalysts.


Asymmetric N-Heterocyclic Carbene Catalyzed Addition of Enals to Nitroalkenes: Controlling Stereochemistry via the Homoenolate Reactivity Pathway To Access δ-Lactams

Nicholas A. White, Daniel A. DiRocco, Tomislav Rovis

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135, 8504-8507 (2013)




An asymmetric intermolecular reaction between enals and nitroalkenes to yield δ-nitroesters has been developed, catalyzed by a novel chiral N-heterocyclic carbene. Key to this work was the development of a catalyst that favors the δ-nitroester pathway over the established Stetter pathway. The reaction proceeds in high stereoselectivity and affords the previously unreported syn diastereomer. We also report an operationally facile two-step, one-pot procedure for the synthesis of δ-lactams.


Catalytic, Asymmetric Indolizidinone Aza-Quaternary Stereocenter Synthesis: Expedient Synthesis of the Cylindricine Alkaloid Core

Derek M. Dalton, Tomislav Rovis

ORGANIC LETTERS 15, 2346-2349 (2013)




The Rh(I)•CKphos catalyzed [2 + 2 + 2] cycloaddition of 1,1-disubstituted alkenyl isocyanates and alkyl alkynes selectively forms previously inaccessible vinylogous amide indolizidinone cycloadducts, establishing an aza-quaternery stereocenter with excellent enantioselectivities (up to 98% ee). This advance enables a seven step catalytic, asymmetric synthesis of the tricyclic core of the cylindricine alkaloids with excellent control of product selectivity as well as regio- and enantioselectivity.