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Featured Event

3/19 - Sigma-Aldrich Lecturer (organic): Bernhard Breit, Albert-Ludwigs-Universität Freiburg

Bernhard Breit - speaker's webpage
Institute of Organic Chemistry and Biochemistry
Albert-Ludwigs-Universität Freiburg
Host: Robert Knowles

Probing New Concepts in Homogeneous Catalysis: From Catalyst Self-Assembly to Propargylic CH-Activation

Tailor-made ligands are essential for efficient selectivity control in homogeneous metal complex catalysis. Since theoretical prediction of an optimal ligand for a given reaction substrate and selectivity problem is impossible, combinatorial approaches to accelerate the catalyst discovery process have emerged. However, this approach still suffers from the limited access towards structurally diverse and meaningful ligand libraries. As a solution to this problem we developed the self-assembly of monodentate to bidentate ligands through complementary hydrogen-bonding. Inspired by DNA base pairing, A–T base pair analogous heterocyclic self-assembly ligand libraries have been generated and evaluated in homogeneous catalysis. Excellent catalysts for regioselective hydroformylation and hydrocyanation as well as asymmetric hydrogenation have emerged. The development of an iterative catalyst library deconvolution strategy allowed to accelerate the catalyst discovery process.1

Conversely, a more classical approach relying on chemical intuition has been applied to develop a new catalytic redox-neutral and atom-economic propargylic CH-activation towards branched allylic esters.2

References:
1. J. Wieland, B. Breit, Nature Chemistry 2010, 2, 832-837.
2. A. Lumbroso, P. Koschker, N. R. Vautravers, B. Breit, J. Am. Chem. Soc. 2011, 133, 2386-2389.