Regio- and Diastereoselective Catalytic Epoxidation of Acyclic Allylic Alcohols with Methyltrioxorhenium: A Mechanistic Comparison with Metal (Peroxy and Peroxo Complexes) and Nonmetal (Peracids and Dioxirane) Oxidants
作者:Waldemar Adam、Catherine M. Mitchell、Chantu R. Saha-Möller
DOI:10.1021/jo9902289
日期:1999.5.1
Geraniol and its 1-methyl derivative (regiochemical probes) and a set of methyl- and tert-butyl-substituted chiral allylicalcohols (stereochemical probes) have been used to elucidate the mechanism of the MTO-catalyzed epoxidation of allylicalcohols. The regiochemical probes are preferentially epoxidized at the unfunctionalized double bond by these MTO-based oxidants, which establishes that MTO/UHP
Copper protection in the palladium catalyzed regioselective allylation of a model polyketide: Methyl 3,5-dioxohexanoate
作者:Jorge Marquet、Marcial Moreno-Mañas、María Prat
DOI:10.1016/s0040-4039(00)99414-0
日期:——
allylation of the model polyketide system methyl 3,5-dioxohexanoate at the C-2 position can be accomplished even with secondary and tertiary radicals by palladium catalyzed allylation of its copper(II) complex, 1a. Initial results indicate that the cobalt(II) complex, 1b, can be also useful. Cyclizations of the resulting diketoesters, 3, afford triaceticacidlactone derivatives, 5, regioselectively allylated
Hydroxy-directed regio-diastereoselective ene reaction of singlet oxygen with chiral allylic alcohols
作者:Waldemar Adam、Bernd Nestler
DOI:10.1021/ja00065a013
日期:1993.6
The photooxygenation of chiral allylic alcohols 1a, (Z)-1f-k, ethers 1b-d, and acetate 1e gave the corresponding hydroperoxy homoallylic alcohols and derivatives 2 through the enereaction with singletoxygen. While the reaction of the acetate 1e proceeded erythro-diastereoselectively as a result of the classical cis effect, for the allylic alcohols 1a and (Z)-1f-k, in which an alkyl group is located
手性烯丙醇 1a、(Z)-1f-k、醚 1b-d 和乙酸酯 1e 的光氧化反应通过与单线态氧的烯反应得到相应的氢过氧高烯丙醇和衍生物 2。由于经典的顺式效应,乙酸酯 1e 的反应以赤型非对映选择性进行,对于烯丙醇 1a 和 (Z)-1f-k,其中烷基位于带羟基的取代基的顺式,高观察到threo选择性。这一发现可以通过立体中心的亲核羟基官能团与进入的亲电子单线态氧亲烯体的配位来解释
Asymmetric allylic substitution by chiral palladium catalysts: Which is more reactive, major π-allyl Pd(II) species or minor π-allyl species?
The reactivity difference of major and minor π-allyl species was examined for two typed asymmetric allylic substitutions via linear symmetrical π-allyl and linear unsymmetrical π-allyl intermediates. 31P NMRobservation of the stoichiometric reaction of [Pd(1,3-diphenyl-π -allyl)(N-P-N-type ligand)]+ with malonate ion verified that major species was much more reactive than the minor one. In the case
Cobalt (II) catalysed allylation of 1,3-dicarbonyl compounds with allyl acetates
作者:Beena Bhatia、M.Madhava Reddy、Javed Iqbal
DOI:10.1016/s0040-4039(00)73737-3
日期:1993.9
An efficient allylation of various 1,3-dicarbonyl compounds can be achived with allyl acetates in the presence of catalytic cobalt (II) chloride in 1,2-dichloroethane.