Terminal alkene monoisomerization catalysts and methods
申请人:San Diego State University Research Foundation
公开号:US09708236B2
公开(公告)日:2017-07-18
The invention provides novel catalysts and methods of using catalysts for controlling the position of a double bond and cis/trans-selectivity in isomerization of terminal alkenes to their 2-isomers. Catalysts such as (pentamethylcyclopentadienyl)Ru formulas 1 and 3 having a bifunctional phosphine can be used in the methods. A catalyst loading of 1 mol % of formulas 1+3 can be employed for the production of (E)-2-alkenes at 40-70° C.; lower temperatures can be used with higher catalyst loading. Acetonitrile-free catalysts can be used at lower loadings, room temperature, and in less than a day to accomplish the same results as catalysts 1+3. The novel catalyst systems minimize thermodynamic equilibration of alkene isomers, so that the trans-2-alkenes of both non-functionalized and functionalized alkenes can be generated.
A straightforward approach to both enantiomers of zearalane is described from the enantiomerically pure alkenol (S)-4, prepared by a kinetic enzymatic resolution of the racemate. The key step is a Pd-catalyzed cross-coupling of an arene trifluoromethanesulfonate with a 9-alkyl-9-borabicyclo[3.3.1]nonane derivative. The two enantiomers 2a and 2b have been obtained in an enantiodivergent manner by macrolactonization
Oxidation of Alcohols with Catalytic Amounts of IBX
作者:Athanassios Giannis、Agnes Schulze
DOI:10.1055/s-2005-924764
日期:——
we present a catalytic IBX-based method for the oxidation of alcohols. Using this system a variety of benzylic alcohols were transformed to aldehydes in good yields whereas secondary alcohols were easily converted to ketones. Primary aliphatic alcohols were oxidised to the corresponding carboxylic acids. 2-Iodobenzoic acid can also be used instead of IBX.
TERMINAL ALKENE MONOISOMERIZATION CATALYSTS AND METHODS
申请人:San Diego State University Research Foundation
公开号:US20150231621A1
公开(公告)日:2015-08-20
The invention provides novel catalysts and methods of using catalysts for controlling the position of a double bond and cis/trans-selectivity in isomerization of terminal alkenes to their 2-isomers. Catalysts such as (pentamethylcyclopentadienyl)Ru formulas 1 and 3 having a bifunctional phosphine can be used in the methods. A catalyst loading of 1 mol % of formulas 1+3 can be employed for the production of (E)-2-alkenes at 40-70° C.; lower temperatures can be used with higher catalyst loading. Acetonitrile-free catalysts can be used at lower loadings, room temperature, and in less than a day to accomplish the same results as catalysts 1+3. The novel catalyst systems minimize thermodynamic equilibration of alkene isomers, so that the trans-2-alkenes of both non-functionalized and functionalized alkenes can be generated.
Alkyltitanium alkoxides generally serve as nucleophiles in reactions with carbonyl compounds and cross-coupling. Their application as reductants is known but remains underdeveloped. Here, we report that irradiation with visible light makes these organometallic compounds efficient reducing agents for the dehalogenation of 1,2- and 1,3-haloalcohols. This reaction was utilized for the reduction of epoxides