title: Intramolecular pyridine-based frustrated Lewis-pairs.
abstract: Deprotonation of the methylpyridines 2,6-lutidine, 2-picoline, 4-dimethylamino-2,6-dimethylpyridine as well as 2,6-dimethyl-4-(piperidine-1-yl)pyridine with n-butyllithium or n-butyllithium/KO-t-Bu at the methyl positions led to the corresponding organolithium or -potassium compounds. Treatment with ClB(C6F5)2 resulted in formation of the 2-borylmethylpyridines py-CH2-B(C6F5)2. They are monomeric and form intramolecular B-N bonds and four-membered rings. A short intramolecular B-N distance was observed in the crystal structure of the dimethylamino-functionalized derivative and proposed to be responsible for the low reactivity of the products towards hydrogen, thf, acetonitrile and CO2. Hydroboration of 6-tert-butyl-2-but-4'-enylpyridine with HB(C6F5)2 led to the corresponding hydroboration product t-Bu-py-(CH2)4-B(C6F5)2 which shows no intramolecular B-N bond formation due to steric crowding. H/D-scrambling experiments with a H2/D2 mixture revealed its reactivity towards hydrogen.
authors.affiliation: Bielefeld University, Faculty of Chemistry, Chair of Inorganic and Structural Chemistry, Centre for Molecular Materials CM2, Universitätsstraße 25, 33615 Bielefeld, Germany. mitzel@uni-bielefeld.de.
authors.forename: Leif A
authors.initials: LA
authors.lastname: Körte
authors.forename: Robin
authors.initials: R
authors.lastname: Warner
authors.forename: Yury V
authors.initials: YV
authors.lastname: Vishnevskiy
authors.forename: Beate
authors.initials: B
authors.lastname: Neumann
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Stammler
authors.forename: Norbert W
authors.initials: NW
authors.lastname: Mitzel