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Light‐Controlled Orthogonal Covalent Bond Formation at Two Different Wavelengths
Author(s) -
Menzel Jan P.,
Feist Florian,
Tuten Bryan,
Weil Tanja,
Blinco James P.,
BarnerKowollik Christopher
Publication year - 2019
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.201901275
Subject(s) - acetonitrile , chemistry , photochemistry , chromophore , covalent bond , wavelength , pyrazoline , solvent , selectivity , reactivity (psychology) , irradiation , organic chemistry , materials science , optoelectronics , catalysis , nuclear physics , medicine , alternative medicine , physics , pathology
We report light‐induced reactions in a two‐chromophore system capable of sequence‐independent λ ‐orthogonal reactivity relying solely on the choice of wavelength and solvent. In a solution of water and acetonitrile, LED irradiation at λ max =285 nm leads to full conversion of 2,5‐diphenyltetrazoles with N ‐ethylmaleimide to the pyrazoline ligation products. Simultaneously present o ‐methylbenzaldehyde thioethers are retained. Conversely, LED irradiation at λ max =382 nm is used to induce ligation of the o ‐methylbenzaldehydes in acetonitrile with N ‐ethylmaleimide via o ‐quinodimethanes, while 2,5‐diphenyltetrazoles also present are retained. This unprecedented photochemical selectivity is achieved through control of the number and wavelength of incident photons as well as favorable optical properties and quantum yields of the reactants in their environment.