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Intramolecular reactions of 1,5‐diaryl‐1,5‐pentadiyl radicals
Author(s) -
Peyman Anuschirwan,
Beckhaus HansDieter,
Rüchardt Christoph
Publication year - 1988
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19881210603
Subject(s) - chemistry , intramolecular force , disproportionation , regioselectivity , stereoselectivity , conformational isomerism , radical , intramolecular reaction , decomposition , stereochemistry , medicinal chemistry , photochemistry , molecule , organic chemistry , catalysis
Photochemical decomposition of 2,6‐diarylcyclohexanones 1a – d yields 1,2‐diarylcyclopentanes 4 and 1,5‐diaryl‐1‐pentenes 5 by intramolecular reaction of the intermediate 1,5‐diaryl‐1,5‐pentadiyls 3 . The two stereoisomers cis ‐ 4 and trans ‐ 4 are formed in equal amounts. There hence exists a 1:1 equilibrium between the two conformers of 3 which lead to cis ‐ and trans ‐ 4 , respectively; the intramolecular combination step itself is not stereoselective. However, the product ratios of 4:5 , i. e. combination: disproportionation, depend on the substituents. This regioselectivity is strongly affected by solvent and temperature.