OXIDATION OF CYCLOALKENES AND METHYLENECYCLOALKANES BY PALLADIUM(II) COMPLEXES .1. NMR-STUDY ON THE MECHANISM OF THE FORMATION OF RING-CONTRACTED AND RING-OPENED PRODUCTS IN THE OXIDATION OF 1-METHYLCYCLOBUTENE
Ie. Beck et al., OXIDATION OF CYCLOALKENES AND METHYLENECYCLOALKANES BY PALLADIUM(II) COMPLEXES .1. NMR-STUDY ON THE MECHANISM OF THE FORMATION OF RING-CONTRACTED AND RING-OPENED PRODUCTS IN THE OXIDATION OF 1-METHYLCYCLOBUTENE, Journal of molecular catalysis, 83(3), 1993, pp. 287-300
Oxidationof 1-methylcyclobutene (1) by PdCl2L2 and PdCl(NO2)L2 (L=CD3C
N) in methylene chloride was studied with H-1 and C-13 NMR. Reaction o
f 1 with PdCl2L2 leads to the formation of the stable ring-opened 1-3-
eta3-pi-allyl palladium complex (2). With the addition of an equimolar
quantity of PdCl(NO2)L2 to the solution of complex 2, the allylic oxi
dation of 2 proceeds slowly via the intermediate formation of another
1-3-eta3-pi-allyl palladium complex (3). When reacting directly with P
dCl(NO2)L2, 1 undergoes palladium (II)-catalyzed ring contraction to g
ive cyclopropyl methyl ketone. Kinetic and spectral data indicate the
formation of an organometallic intermediate, a product of the beta-nit
ritopalladation of the parent olefin 1.