Interlaced capsules by self-assembly of cavitands substituted with tripeptides and tetrapeptides

<p>A strategy that utilizes macrocyclic resorcin[4]arenes for the pre-positioning of peptides to form cavitands that subsequently self-assemble through hydrogen bonds was used for the formation of molecular capsules. Hydrophobic tri- and tetrapeptides were attached via their <i>C</i>-termini to tetraformylresorcin[4]arene using acylhydrazone linkers. The resulting cavitands self-assemble in relatively non-polar environments (chloroform or chloroform-methanol) forming non-covalent dimers through hydrogen bonding motifs resembling beta-sheets. NMR studies (ROESY and DOSY) indicate that the binding motif involves <i>C</i>-terminal amino acids from the peptide strands, while the <i>N</i>-terminal parts are positioned outside of the cavity. The capsules possess stable porous structures and they are able to quantitatively complex fullerenes C₆₀ and C₇₀.</p

The Inverse Demand Oxa-Diels–Alder Reaction of Resorcinarenes: An Experimental and Theoretical Analysis of Regioselectivity and Diastereoselectivity

The Diels–Alder reaction enables introduction of new functionalities onto the resorcinarene skeleton with simultaneous generation of new stereogenic centers and expansion of the internal cavity. We present highly regio- and diastereoselective inverse electron demand oxa-Diels–Alder reactions of resorcinarene <i>ortho</i>-quinone methide with benzofuran and indene, each generating 12 new stereogenic centers. The mechanism and reasons for regioselectivity and diastereoselectivity were analyzed using theoretical calculations (NBO charges, Fukui functions, transition state energies, and thermodynamic stability of the products). Enantiomers were separated, and their configurations were determined by comparison of experimental and theoretical electronic circular dichroism spectra

The Inverse Demand Oxa-Diels–Alder Reaction of Resorcinarenes: An Experimental and Theoretical Analysis of Regioselectivity and Diastereoselectivity

The Diels–Alder reaction enables introduction of new functionalities onto the resorcinarene skeleton with simultaneous generation of new stereogenic centers and expansion of the internal cavity. We present highly regio- and diastereoselective inverse electron demand oxa-Diels–Alder reactions of resorcinarene <i>ortho</i>-quinone methide with benzofuran and indene, each generating 12 new stereogenic centers. The mechanism and reasons for regioselectivity and diastereoselectivity were analyzed using theoretical calculations (NBO charges, Fukui functions, transition state energies, and thermodynamic stability of the products). Enantiomers were separated, and their configurations were determined by comparison of experimental and theoretical electronic circular dichroism spectra