Asymmetric Allylation of Ketones and Subsequent Tandem Reactions Catalyzed by a Novel Polymer-Supported Titanium-BINOLate Complex
作者:Jagjit Yadav、Gretchen R. Stanton、Xinyuan Fan、Jerome R. Robinson、Eric J. Schelter、Patrick J. Walsh、Miquel A. Pericas
DOI:10.1002/chem.201400204
日期:2014.6.2
asymmetric allylation of ketones. The catalyst showed good activity and excellent enantioselectivity, typically matching the results obtained in the corresponding homogeneous reaction. The allylation reaction mixture could be submitted to epoxidation by simple treatment with tert‐butyl hydroperoxide (TBHP), and the tandem asymmetricallylation epoxidation process led to a highly enantioenriched epoxy alcohol
Traceless OH-Directed Wacker Oxidation-Elimination, an Alternative to Wittig Olefination/Aldol Condensation: One-Pot Synthesis of <i>α</i>,<i>β</i>-Unsaturated and Nonconjugated Ketones from Homoallyl Alcohols
作者:Venkati Bethi、Rodney A. Fernandes
DOI:10.1021/acs.joc.6b01899
日期:2016.9.16
A new method for one-pot synthesis of β-substituted and β,β-disubstituted α,β-unsaturated methyl ketones from homoallyl alcohols by sequential PdCl2/CrO3-promoted Wacker process followed by an acid-mediated dehydration reaction has been developed. Remarkably, internal homoallyl alcohols delivered regioselectively nonconjugated unsaturated carbonyl compounds under the same protocol. A new starting material-based
efficiently undergo nucleophilic addition reactions with allylstannanes in the presence of GdCl3·6H2O in acetonitrile under extremely mild reaction conditions to give the corresponding homoallylic alcohols in excellent yields and with high chemoselectivity.
mild catalytic allylation of carbonyl compounds, applicable to aldehydes, ketones, and imines is developed using allyltrimethoxysilane as the allylating reagent. The reaction proceeds smoothly with 1-10 mol % of CuCl and TBAT in THF at ambient temperature. Mechanism studies indicated that the copper alkoxide, allylfluorodimethoxysilane, and allyltrimethoxysilane are essential to promote the reaction
The Mechanism and an Improved Asymmetric Allylboration of Ketones Catalyzed by Chiral Biphenols
作者:David S. Barnett、Philip N. Moquist、Scott E. Schaus
DOI:10.1002/anie.200904715
日期:2009.11.2
Giving it a boost: A mechanistic study of the enantioselective asymmetric titled reaction with allyldiisopropoxyborane catalyzed by chiralbiphenols revealed a key ligand exchange process which liberates isopropyl alcohol. The addition of iPrOH to the reaction increases the overall rate and enantioselectivity. As a result an improved reaction, employing allyldioxaborinane with 1 and tBuOH, resulted