Co(III)−Alkyl Complex- and Co(III)−Alkylperoxo Complex-Catalyzed Triethylsilylperoxidation of Alkenes with Molecular Oxygen and Triethylsilane
摘要:
[GRAPHICS]Both a Co(III)-alkyl complex and a Co(III)-alkylperoxo complex were found to catalyze triethylsilylperoxidation of alkenes with O-2 and Et3SiH. On this basis, together with the nonstereoselectivity in the Co(II)-catalyzed peroxidation of 3-phenylindene and the formation of the corresponding 1,2-dioxolane from 2-phenyl-1-vinylcyclopropane (a radical clock), we propose a reasonable mechanism for the Co(II)-catalyzed novel autoxidation of alkenes with Et3SiH discovered by Isayama and Mukaiyama.
As the first unambiguous syntheses and characterization of the tetrakis(1-pyrazolyl)borato}lanthanide(III) complexes, stable eight-coordinate (β-ketoenolato)samariums [Smη3-B(pz)4}2(β-ketoenolato)] (pz = 1-pyrazolyl group) were prepared, and novel stereochemically non-rigid temperature-dependent motions of the B(pz)4 ligands were observed on their solution-state 1H-NMR spectra, showing the spectroscopic
Co-catalyzed autoxidation of alkene in the presence of silane. The effect of the structure of silanes on the efficiency of the reaction and on the product distribution
A systematic investigation of the structural effect of silanes on the Co-catalyzed reductive oxygenation of alkene in the presence of silane (Mukaiyama-Isayama reaction) showed that the efficiency of the reaction decreases with the increase of the steric bulk of the silanes. A similar trend was observed for the metal-exchange reaction between Co(III)-alkylperoxo complex and silane, too. The peroxidation of (S)-limonene, followed by deprotection of the derived silyl peroxides, provides a mixture of the corresponding monocyclic hydroperoxide 24 and the bicyclic one 25, the ratio being a marked function of the steric bulk of silanes. (c) 2005 Elsevier Ltd. All rights reserved.
ISAYAMA, SHIGERU;MUKAIYAMA, TERUAKI, CHEM. LETT.,(1989) N, C. 573-576