Carbenoid Chemistry :
Furanoses serve as useful platforms upon which to investigate the intra- and inter-molecular chemistry of an attached carbenoid species. MS students in the group have shown that this is quite useful for the synthesis of optically active ethers and bicyclic furans. The rigid furanose platform limits the possibilities for intramolecular C-H insertion leading to stereospecific insertions on various precursors (Carbohydr. Res. 2008).
Following an unexpected discovery in a chiral furanose-based system, suitably substituted azide-diazo precursors are being studied as a general route to various nitrogen heterocycles. Metal-catalyzed diazo decomposition could give access to medium- and large-sized heterocycles. We have isolated 7- and 14-membered ring heterocycles from sugar- and non-sugar-derived precursors and proved their structures through X-ray crystallography.
As part of our interest in the use of azides and diazo compounds we have developed several novel methods for azide synthesis. Arylsulfonyl azides are found to safe alternatives to current protocols and we have studied their use in the parallel synthesis of alkyl and acyl azides. These methods are amenable to microwave-assisted synthesis and we have now developed one-pot syntheses of sugar-derived azides from the parent alcohols (Tetrahedron. Lett. 2011).
These are important components of various biological systems including the protective capsules of pathogenic bacteria such as S. aureus. We have synthesized analogs of the parent aminosugars using parallel synthesis techniques with the goal of producing inhibitors of the enzymes responsible for capsule production (J. Carbohydr. Chem. 2012).
We are always looking out for lab preps, mainly from the carbohydrate literature, that could be turned into useful learning experiences for undergraduates. Previous examples include accesible elimination and substitution reactions, and most recently we have published on a very useful bimolecular substitution, with the stereochemical inversion being observed through a change in proton-proton coupling constants (J. Chem. Ed. 2012).