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Flow Photochemical Syntheses of trans‐ Cyclooctenes and trans‐ Cycloheptenes Driven by Metal Complexation
Author(s) -
Pigga Jessica E.,
Fox Joseph M.
Publication year - 2020
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201900085
Subject(s) - chemistry , cycloalkene , stereospecificity , flow chemistry , isomerization , photoisomerization , cis–trans isomerism , bioorthogonal chemistry , photochemistry , flow (mathematics) , combinatorial chemistry , organic chemistry , catalysis , click chemistry , geometry , mathematics
trans ‐Cyclooctenes and trans ‐cycloheptenes have long been the subject of physical organic study, but the broader application had been limited by synthetic accessibility. This account describes the development of a general, flow photochemical method for the preparative synthesis of trans ‐cycloalkene derivatives. Here, photoisomerization takes place in a closed‐loop flow reactor where the reaction mixture is continuously cycled through Ag(I) on silicagel. Selective complexation of the trans‐ isomer by Ag(I) during flow drives an otherwise unfavorable isomeric ratio toward the trans ‐isomer. Analogous photoreactions under batch‐conditions are low yielding, and flow chemistry is necessary in order to obtain trans ‐cycloalkenes in preparatively useful yields. The applications of the method to bioorthogonal chemistry and stereospecific transannulation chemistry are described.