Cyclopalladation of (S)-4-tert-Butyl-2-methyl-2-oxazoline: An Unprecedented Case of (sp3)C-H Bond Activation Resulting in exo-Palladacycle Formationстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 14 сентября 2013 г.
Аннотация:Direct cyclopalladation of (S)-4-tert-butyl-2-methyl-2-oxazoline at the nonactivated tert-butyl
group using palladium(II) acetate in acetic acid afforded the first example of an
oxazoline-derived exo-palladacycle with an (sp3)C-Pd bond. The structure of the new
palladacycle was established using spectroscopic and X-ray studies of the myu-chloro-dimeric
complex 2 and two mononuclear triphenylphosphane derivatives: neutral adduct 4 and its
cationic benzonitrile-phosphane analogue 5. Analysis of NMR data for compounds 4 and 5
suggests a highly puckered lambda(S) conformation of the palladacycle in solution. The X-ray crystal structure of cationic complex 5 confirmed the same highly puckered lambda(S) conformation of the palladacycle in the solid state; in addition, it revealed unusual pi-pi-interactions between the phenyl rings of the benzonitrile and PPh3 ligands and a distorted M-propeller configuration of the PPh3 fragment.