[EN] CATALYTICS ASYMMETRIC ACTIVATION OF UNACTIVATED C-H BONDS, AND COMPOUNDS RELATED THERETO [FR] ACTIVATION CATALYTIQUE ASYMETRIQUE DE LIAISONS C-H INACTIVEES ET COMPOSES ASSOCIES
作者:Irina P. Smoliakova、Jessica L. Wood、Valeria A. Stepanova、Relindis Y. Mawo
DOI:10.1016/j.jorganchem.2009.10.040
日期:2010.2
Tertiary, secondary and primarybenzylamines, as well as structurally different oxazolines readily reacted with Pd(OAc)2 on silica gel to form cyclopalladated complexes containing a five or six-membered palladacycle with a (sp2)C–Pd or (sp3)C–Pd bond. The complexes were obtained in 45–98% yield, which is comparable with or exceeds the yields reported for preparation of the same compounds in solution
Synthesis and structural characterization of enantiopure exo and endo six-membered oxazoline-derived palladacycles
作者:Relindis Y. Mawo、Diane M. Johnson、Jessica L. Wood、Irina P. Smoliakova
DOI:10.1016/j.jorganchem.2007.10.011
日期:2008.1
Direct palladation of (S)-4-beiizyl-2-methyl-2-oxazoline (1) and (S)-2-benzyl-4-tet-t-butyl-2-oxazoline (2) using Pd(OAC)(2) in MeCN afforded the corresponding mu-acetato-dimeric complexes with six-membered exo and endo palladacycles, respectively. The same complexes were obtained by reacting coordination complexes Pd(1)(2)(OAC)(2) and Pd(2)(2)(OAc)(2) with Pd(OAc)(2) in MeCN. Metalation of (S)-2,4-dibenzyl-2-oxazoline (3) with Pd(OAc)(2) in AcOH, MeCN or CH2CL2 resulted in the regiospecific formation of the six-membered endo palladacycle. The obtained mu-acetato-dimeric complexes were converted to the corresponding mu-chloro-dimeric derivatives 7, 11 and 13 by treatment with LiCl in acetone. The mononuclear PPh3 adducts 8, 12 and 14 were obtained by reacting dimers 7, 11 and 13 with PPh3 in benzene. NMR spectroscopy data supported the proposed structures of all complexes and suggested that exo and endo palladacycles in 8 and 12 have rigid boat conformations in CHCl3. The X-ray crystal structures of the mu-acetato dimer 6 with the exo palladacycle and the PPh3 adduct 14 with the endo metalacycle revealed boat conformation of both palladacycles and chiral twisted conformations delta(S) and lambda(S), respectively, of the oxazoline rings in the solid state. (c) 2007 Elsevier B.V. All rights reserved.