Seminar: Prof. Jérôme Lacour - From Cationic Helicenes to [3+X+3+X] Macrocyclizations – Chemical Platforms to Ubiquitous Applications

Tuesday, 6 March 2018 - 12:00pm – Tuesday, 6 March 2018 - 1:00pm  |  CHEMSCI M11

Speaker: Prof. Jérôme Lacour

Recent studies on the synthesis and properties of cationic [4] and [6]helicenes will be presented.[1] Some of these derivatives can be prepared on gram-scale in two steps only. Single enantiomers display original biological, chemical and physical properties.[2] A focus will be given on regio-divergent post-functionalization routes,[3] as late introduction of subtituents allows a tuning of many properties, among which electronic absorption, circular dichroism and fluorescence near or within the biological transparency window.[4] Recent progress on metal-catalyzed reactions and processes will also be presented – and those involving dirhodium,[5] CpRu [6] and copper [7] catalyzed decompositions of α-diazocarbonyls in particular. An attention will be given to routes affording ylide intermediates and then functionally rich heterocyclic derivatives. A large variety of stereoselective and enantiospecific transformations are available through these metal carbene reactions. For instance, straightforward syntheses of chiral crown-ethers, on large scale (ca. 20 g) in two steps only from 1,4-dioxane, will be presented.[8] Mechanistic investigations and derived applications will be particularly detailed during the lecture.[9]