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Synthesis of Dibromobenzobarrelene Derivatives and Catalytic Activity of Their Rhodium Complexes
Author(s) -
Schlesinger Maik,
Hofmann Max,
Rüffer Tobias,
Schaarschmidt Dieter,
Lang Heinrich,
Theilacker Sergio,
Schürmann Markus,
Jurkschat Klaus,
Mehring Michael
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201300161
Subject(s) - chemistry , phenylboronic acid , mesitylene , rhodium , catalysis , cycloaddition , medicinal chemistry , enone , carboxylic acid , diene , stereochemistry , organic chemistry , natural rubber
Abstract A novel synthetic route based on [4+2] cycloaddition for dibromobenzobarrelene derivatives starting from in situ generated 3,5‐dibromo‐1,2‐didehydrobenzene and mesitylene, 1,2,4,5‐tetramethylbenzene, 1,2,3,5‐tetramethylbenzene, pentamethylbenzene, 1,3‐dimethoxybenzene, and 2,4,6‐trimethylbromobenzene, respectively, was developed. Thus, six novel dibromobenzobarrelenes with diverse substitution patterns at the barrelene framework including chiral derivatives are reported. The benzobarrelene 6,8‐dibromo‐1,3,10‐trimethyl‐1,4‐dihydro‐1,4‐ethenonaphthalene ( 1a ) was functionalized at the annulated benzene ring to give three novel carboxylic acids and two novel phosphonic acid esters. Selected benzobarrelene complexes with Rh I Cl were tested for their catalytic activity in the 1,4‐addition of phenylboronic acid towards cyclohex‐2‐enone. Turnover frequencies up to 3405 h –1 were observed, which are among the highest reported so far for Rh–diene complexes in this type of C–C coupling reaction.