Four newsigmatropicsequences triggered by the regiocontrolled [2,3]-Wittig rearrangement of unsymmetrical bis-allylic ethers (1) to the l,5-dien-3-ols (2) arc described, which provide unique, regiocontrolled methods for the synthesis of a wide variety of unsaturatedcarbonylcompounds possessing interesting molecular frameworks. The newly developed sequences include the [2,3]-Wittig-Claisen, the
Sterically Directed Iridium-Catalyzed Hydrosilylation of Alkenes in the Presence of Alkynes
作者:Jill A. Muchnij、Farai B. Kwaramba、Ronald J. Rahaim
DOI:10.1021/ol5000549
日期:2014.3.7
A selective iridium catalyzed hydrosilylation of alkenes in the presence of more reactive alkynes is described. By utilizing [IrCl(COD)]2 in the presence of excess COD, hydrosilylation of alkenes and alkynes with ethynylsilanes is achieved with good chemo- and regioselectivity. This approach goes against the traditional reactivity trends of platinum and rhodium catalysts and allows access to highly
A process for the preparation of an olefinically unsaturated ether
申请人:SHELL INTERNATIONALE RESEARCH
MAATSCHAPPIJ B.V.
公开号:EP0025240A1
公开(公告)日:1981-03-18
A process for the preparation of an olefinically unsaturated ether by reacting a conjugated diene and a lower alkanol with the aid of an acidic catalyst, in which process a non-basic aprotic polar solvent, such as methyl ethylketone or sulfolane, is used in order to increase the selectivity. As conjugated diene butadiene is preferred. Butadiene may be used together with isobutene, n-butenes and butanes.
Air-drying compositions for treating fibrous substrates
申请人:MONSANTO COMPANY
公开号:EP0048599A1
公开(公告)日:1982-03-31
Polymer compositions are described that confer an enhanced balance of wet and dry strength properties to a cellulosic substrate while leaving the substrate soft and porous. The compositions comprise a hydrophilic air-curing polymer and a polyol with a carbon to oxygen ratio of less than 3:1, typified by glycerol.
A process is described in which polymerization of a free-radical polymerizable monomer is initiated using as initiator a prepolymerizate obtained by oxidative polymerization of a compound having at least two unsaturations that are each a, β or β, y to nucleophilic groups activating the unsaturation towards oxidative polymerization. The initiators are stable but reactive and actually enter into the polymerization reaction, permitting the product to be tailored to the desired end use. They can work in the presence of oxygen if desired.