Mass Spectrometry in Structural and Stereochemical Problems. CCXVII. Electron Impact Promoted Fragmentation of <i>O</i>-Methyl Oximes of some α,β-Unsaturated Ketones and Methyl Substituted Cyclohexanones
作者:Younus M. Sheikh、Raymond J. Liedtke、A. M. Duffield、Carl Djerassi
DOI:10.1139/v72-444
日期:1972.9.1
delineate the modes of mass spectrometric fragmentation of O-methyl oximes of α,β-unsaturated ketones and methyl substituted cyclohexanones. α,β-Unsaturated ketone and 2- and 4-methylcyclohexanone O-methyl oxime ether derivatives fragment upon electron impact in a manner reminiscent of the carbonyl derivatives from which they were prepared. However, several fragmentation sequences characteristic of the O-methyl
Control of Aldol Reaction Pathways of Enolizable Aldehydes in an Aqueous Environment with a Hyperbranched Polymeric Catalyst
作者:Yonggui Chi、Steven T. Scroggins、Emine Boz、Jean M. J. Fréchet
DOI:10.1021/ja806584q
日期:2008.12.24
proline that can eliminate the self-aldol reactions by suppressing an irreversible aldol condensation pathway. Control experiments and preliminary mechanistic studies suggest that the polymer catalyst provides an optimum environment for the aldol reaction to proceed selectively in water, and the catalytic conditions provided by the polymer are difficult to duplicate with typical small molecule analogues
Aza-Michael addition of amines, including aromatic and aliphatic amines, with α, β-unsaturated ketones was realized employing N-Heterocyclic Carbene (NHC) as organocatalyst, yielding β-amino ketones with up to 98% yield.
Catalyst for asymmetric epoxidation of enones and process for producing optically active epoxide employing it
申请人:——
公开号:US20010051737A1
公开(公告)日:2001-12-13
A complex catalyst for asymmetric epoxidation of enones, which comprises:
(A) an optically active binaphthol,
(B) lanthanum triisopropoxide,
(C) triphenylphosphine oxide, and
(D) cumene hydroperoxide or tert-butyl hydroperoxide.