Photocatalysis has recently opened up new avenues for the generation of radical species under visible light irradiation conditions. A particularly fascinating class of photocatalyzed transformations relies on the activation of stable boron species with visible-light since it allows the creation of boryl and/or carbon radicals through single electron transfer or energy transfer without the need for specific and costly equipment. This new paradigm has found numerous applications in synthetic organic chemistry, catalysis, and macromolecular chemistry. In this minireview, the concepts underlying photoactivation of boron-species as well as applications to the creation of C-H, C-C, C-O, B-C and B-S bond are discussed.
2015-02- Sonogashira reactions for the synthesis of polarized pentacene derivatives
Schweizer, S.; Erbland, G.; Bisseret, P.; Lalevée, J.; Le Nouën, D.; Blanchard, N., Turkish J. Chem. 2015, 39, 1180-1189.
Five dissymmetrically functionalized anthracene analogues were synthesized from commercially available 9,10-dibromoanthracene through an efficient bromine-iodine exchange followed by two successive Sonogashira coupling reactions. The resulting TMS-anthracene analogues are interesting building blocks for the preparation of highly pi-conjugated dissymmetric pentacene-based dyads, which could be used as active semiconducting layers for organic field-effect transistors (OFETs).
Inflammation adversely affects the health of millions of people worldwide, and there is an unmet medical need for better anti-inflammatory drugs. We evaluated the therapeutic interest of mycolactone, a polyketide-derived macrolide produced by Mycobacterium ulcerans. Bacterial production of mycolactone in human skin causes a combination of ulcerative, analgesic, and anti-inflammatory effects. In addition to establishing the anti-inflammatory potency of mycolactone in vivo, our study therefore highlights the translational potential of mycolactone core-derived structures as prospective immunosuppressants.
The hydrometalation of alkynes with group 14 elements such as tin- or silyl hydrides is a classical transformation in organic synthesis. Strangely, among the group 14 elements, the use of germanium hydrides is rarely seen. Two efficient, stereodivergent, and broadly applicable routes to (Z)- and (E)-α-CF3-vinylgermanes by regio- and stereoselective hydrogermylation of α-trifluoromethylated alkynes under radical or transition-metal-catalyzed conditions are reported.
In this chapter are summarized a personal account of 9 years of research in the field of human Mycobacterium ulcerans infection, from both a chemical perspective and in close collaboration with biologists of the Institut Pasteur in Paris. This dramatic necrotizing skin disease affects mainly the African continent and is caused by an exotoxin called mycolactone A/B that is secreted by M. ulcerans. Thanks to modular synthetic strategies, we have forged a unique collection of mycolactone A/B analogs, including fluorescent ones that have been essential in the exploration of the biology of the disease. Fascinating discoveries were made during this odyssey, not only from both a chemical and biological standpoint but also from a more human perspective.
