Titre : Catalytic methods for addressing challenges in site-selectivity and regioselectivity
Heure : 11h00
Campus MIL, Local : A-3541
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Abstract. Site-selectivity and regioselectivity are core issues in organic synthesis. I will describe two ongoing projects aimed at developing modes of catalytic reactivity that enable control of these types of selectivity in useful contexts. Mechanistic and computational studies of the processes will be discussed.
- Site-selective transformations of O–H and C–H bonds in carbohydrates. Sugars present a classic challenge in site-selectivity, possessing multiple hydroxy groups in similar steric and electronic environments. My group has taken advantage of the reversible covalent interactions of boron compounds with diols to achieve catalyst-controlled, selective O-functionalizations. More recently, we have turned our attention to the C–H bonds in sugars, using photocatalytic hydrogen atom transfer to achieve site-selective radical formation.
- Regioselective functionalizations of azole heterocycles. Azoles are ambident nucleophiles that give rise to regioisomers upon N-functionalization. My group has shown that organoboron catalysis can be used to activate various azole types, including pyrazoles, triazoles, tetrazoles and purines, towards regioselective reactions with diverse electrophiles. Examples of synergistic organoboron/transition metal catalysis, and applications in N-glycoside synthesis, will be highlighted.
