Alkoxyamine-derived formamidines: configurational control and molecular folding

Expedient synthesis of highly substituted 3,4-dihydro-1,2-oxathiine 2,2-dioxides and 1,2-oxathiine 2,2-dioxides: revisiting sulfene additions to enaminoketones

The addition of sulfenes to substituted enaminoketones, followed by a facile Cope elimination, provides efficient access to a diverse series of 1,2-oxathiine 2,2-dioxides.

Peptidines: glycine-amidine-based oligomers for solution- and solid-phase synthesis

Efforts to emulate biological oligomers have given rise to a host of useful technologies, ranging from solid-phase peptide and nucleic acid synthesis to various peptidomimetic platforms. Herein we introduce a novel class of peptide-like oligomers called "peptidines" wherein each carbonyl O-atom within poly-N-alkyl glycine oligomers is replaced with a functionalized N-atom. Compared to peptoids or peptides, the presence of this amidine N-substituent in peptidines effectively doubles the number of diversification sites per monomeric unit, and can decrease their overall conformational flexibility. We have developed iterative solution- and solid-phase protocols for the straightforward assembly of peptidines containing diverse backbone and amidine substituents, derived from readily available primary and secondary amines. We have also performed crystallographic and computational studies, which demonstrate a strong preference for the trans (E) amidine geometry. Given their straightforward synthetic preparation and high functional group density, peptidines have the potential to serve as useful tools for library generation, peptide mimicry, and the identification of biologically active small molecules.

Z-formamidoximes in molecular folding and macrocycles

The formamidoxime configurational Z isomer coupled with the pyridylbiscarboxamide conformational codon were used to fold planar, curved structures. When embedded into macrocycles, this folded motif promotes dimerization through π-π stacking and hydrogen-bonding and the formation of tubules akin to molecular channels in the solid state.