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Syntheses of Tetrasubstituted [10]Cycloparaphenylenes by a Pd‐catalyzed Coupling Reaction. Remarkable Effect of Strain on the Oxidative Addition and Reductive Elimination
Author(s) -
Kayahara Eiichi,
Nakano Masaya,
Sun Liansheng,
Ishida Kosuke,
Yamago Shigeru
Publication year - 2020
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202000711
Subject(s) - reactivity (psychology) , aryl , oxidative addition , catalysis , chemistry , trifluoromethanesulfonate , reductive elimination , alkyl , coupling reaction , strain (injury) , oxidative coupling of methane , oxidative phosphorylation , combinatorial chemistry , medicinal chemistry , organic chemistry , medicine , biochemistry , alternative medicine , pathology
A small library of tetrasubstituted [10]cycloparaphenylene ([10]CPP) derivatives bearing alkyl, alkenyl, alkynyl and aryl substituents was constructed by a Pd‐catalyzed cross‐coupling reaction starting from tetratriflate [10]CPP 5 e , which was readily available in high yields on a >2 g scale. The CPP skeleton increases the reactivity of aryl triflate for oxidative addition to the Pd species, and 5 e is 10 times more reactive than its linear paraphenylene analogue, as determined by competition experiments. Theoretical calculations suggest that the accumulation of the small strain relief from each paraphenylene unit not involved in the reaction is responsible for the observed enhanced reactivity.