| dc.description.abstract | The amide bond is one of the most important linkages in organic chemistry and constitutes the key functional group in peptides, polymers, and many natural products and pharmaceuticals. Purely chemical methods have been developed for the preparation of amides, but most utilize a dehydrative approach, some involving the use of coupling reagents. However, there are drawbacks to this methodology, and although other conceptually innovative alternatives exists, there is still a need for more viable alternative methods to target an increasing list of complex problems in amide synthesis. Here we present a conceptually new approach to amide synthesis and its application to the enantioselective synthesis of β,γ-dihydroxyamides. Instead of a conventional approach which involves a nucleophilic addition-elimination reaction by the amine on an electrophilic active ester derivative, our approach uses an α-bromo nitroalkane as an acyl donor for an amine. N-Iodosuccinimide is used to activate the amine, and potassium carbonate is used to maintain mildly alkaline condition. This reaction, in combination with Sharpless asymmetric dihydroxylation provides access to a variety of enantioenriched aromatic and aliphatic β,γ-dihydroxyamides without any epimerization, hydroxy γ-lactone formation or α-hydroxy aldehyde formation via retro-aldol reaction. This combination of entirely enantioselective methods and α-bromonitromethane-amine coupling may ultimately enable the efficient fully chemical synthesis of chiral non-racemic unnatural peptides and other biologically active natural products. | |
