Shafir

Research group

FULL REPORT

Abstract

At the Shafir laboratory we are interested in developing new chemical transformations, both in the context of fine chemical and commodity applications. In 2015, the principle direction involved the hypervalent activation of organoiodines for the oxidative carbon-carbon and carbon-nitrogen bond-forming reactions, with the emphasis in retaining the iodine functionality for downstream diversification. Along these lines, we discovered a method for the TM-free coupling of iodoarenes with ketones (α-arylation). This unusual carbon-carbon coupling takes place ortho to the iodine, leaving the iodine untouched. The regioselectivity thus attained complements the ipso-selective metal-catalyzed (Pd, Cu) α-arylation. The coupling allows for the synthesis highly hindered all-carbon quaternary centers. In another application, the group developed a relay route towards 1,5-imidazoles derivatives, a highly sought out compound family inaccessible by many common imidazole functionalization approaches. As part of our work on heterocycle activation, we prepared a series of unusual aryl λ3 iodanes containing an unprotected NH-imidazole. A combination of the hypervalent iodine chemistry with Cu-catalyzed C-N coupling now offers the possibility to access the hindered N-aryl-5-iodomidazole core. The approach is highly divergent, as the iodine atom now ushers the synthesis of a wide variety of 1,5-imidazole derivatives.

The group has also initiated studying the application of Zr-based metal-organic frameworks (MOF), as highly promising catalyst platform. Given the crucial role played by the Zr MOF structure defects, we have developed a method for controlling the prevalence and chemical nature of such defects through controlled modulation. In a subsequent study, proline modulation has been introduced, offering a highly controlled growth of a wide variety of Zr metal-organic frameworks.

Topics addressed

  • New oxidative C-C and C-N coupling
  • Control for the MOF structure via acid modulation

Articles

“Hypervalent Activation as a Key Step for Dehydrogenative ortho C-C Coupling of Iodoarenes”
Chem. Eur. J. (2015) 21, 18779–18784
Y. Wu, Ismael Arenas, L. M. Broomfield, Eddy Martin, A. Shafir