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λ ‐Orthogonal Pericyclic Macromolecular Photoligation
Author(s) -
Hiltebrandt Kai,
Pauloehrl Thomas,
Blinco James P.,
Linkert Katharina,
Börner Hans G.,
BarnerKowollik Christopher
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201410789
Subject(s) - maleimide , pericyclic reaction , tetrazole , macromolecule , chemistry , functional group , polymer , imine , photochemistry , functional polymers , nitrile , isocyanate , azobenzene , polymer chemistry , organic chemistry , polymerization , polyurethane , biochemistry , catalysis
A photochemical strategy enabling λ‐orthogonal reactions is introduced to construct macromolecular architectures and to encode variable functional groups with site‐selective precision into a single molecule by the choice of wavelength. λ‐Orthogonal pericyclic reactions proceed independently of one another by the selection of functional groups that absorb light of specific wavelengths. The power of the new concept is shown by a one‐pot reaction of equimolar quantities of maleimide with two polymers carrying different maleimide‐reactive endgroups, that is, a photoactive diene (photoenol) and a nitrile imine (tetrazole). Under selective irradiation at λ=310–350 nm, any maleimide (or activated ene) end‐capped compound reacts exclusively with the photoenol functional polymer. After complete conversion of the photoenol, subsequent irradiation at λ=270–310 nm activates the reaction of the tetrazole group with functional enes. The versatility of the approach is shown by λ‐orthogonal click reactions of complex maleimides, functional enes, and polymers to the central polymer scaffold.