Acceleration and regioselectivity switching in 1,3-dipolar cycloaddition reactions confined in a bis-calix[4]pyrrole cage.

ABSTRACT: We report the results of our investigations on the role of the octa-imine bis-calix[4]pyrrole cage 1 in mediating confined 1,3-dipolar cycloaddition reactions of a series of 4-azido(alkyl)-pyridine-N-oxides (alkyl = null, Me, Et; 2a-c) with 1-(2-propynyl)-4(1H)-pyridinone (4). We performed ¹H NMR binding studies of the different substrates with the octa-imine cage, evidencing the formation of thermodynamically and kinetically highly stable inclusion homo-complexes featuring 1 : 1 and 2 : 1 stoichiometry. We used simulated speciation profiles and performed ITC experiments to thermodynamically characterize the formed complexes. Adding mixtures of an azido-derivative with the propynyl-pyridinone in a solution of cage 1 resulted in the formation of the expected 1 : 1 a

SUBMITTER: Li Y 

PROVIDER: S-EPMC12269890 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature