Nano-dispersed platinum(0) in organically modified silicate matrices as sustainable catalysts for a regioselective hydrosilylation of alkenes and alkynes
作者:Brett J. Duke、Evan N. Akeroyd、Shreeja V. Bhatt、Chibueze I. Onyeagusi、Shreya V. Bhatt、Brandy R. Adolph、Jean Fotie
DOI:10.1039/c8nj01889h
日期:——
a uniform particles distribution produced higher and consistent yields, while those with poor particles distribution produced lower and almost random yields, suggesting that the uniformity in particle distribution, and by extension the nature of the siloxane matrix, are important for the catalytic properties of these materials. The scope of the reaction was broadened to a range of olefins, with a goal
Nucleophilic Iron Catalysis in Transesterifications: Scope and Limitations
作者:Silja Magens、Bernd Plietker
DOI:10.1021/jo1004636
日期:2010.6.4
The ester bond is one of the most common structural motifs found in nature. Apart from the condensation between an acid and an alcohol, transesterifications represent another mechanistic alternative for the preparation of this compound class. The present paper summarizes our most recent investigations in this field, using nucleophilic iron complexes as catalysts for transesterifications under neutral conditions. This new type of metal catalyst complements the existing methodologies, which rely on Lewis acidic metal complexes. Investigations on scope and limitations, stereochemical course, and chemoselectivities will be presented.
US6262287B1
申请人:——
公开号:US6262287B1
公开(公告)日:2001-07-17
Zirconocene-catalyzed direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1 : 1 ratio under solvent-free conditions
作者:Zhi Tang、Qiutao Jiang、Lifen Peng、Xinhua Xu、Jie Li、Renhua Qiu、Chak-Tong Au
DOI:10.1039/c7gc02174g
日期:——
A highlyefficient way for direct (trans)esterification of acyl acids(esters) and alcohols in a strictly 1:1 ratio using zirconocene complex (1, 1 mol%), a strong Lewis acid of good water tolerance, as catalystundersolvent-free condition has been developed. A wide range of acids and alcohols(esters) substrates undergo (trans)esterification to produce carboxylic ester motifs in moderate to good or
Organosiloxane fragrance precursor compounds having at least one organosiloxane unit of the formula
or a mixture thereof
and if any other siloxane unit(s) in the said organosiloxanes being present this/these is/are of formula
wherein R represents a substituted or unsubstituted C1-8 alkyl group or a substituted or unsubstituted aryl group;
R″ represents a hydrogen atom, a monovalent C1-8 hydrocarbon group or a monovalent C1-8 halogenated hydrocarbon group;
R1 represents a hydrogen atom or a substituted or unsubstituted C1-8 alkyl group or a substituted or unsubstituted aryl group or a bond connecting CR1 and CR3;
R3 represents a hydrogen atom or a substituted or unsubstituted C1-8 alkyl group or a substituted or unsubstituted aryl group;
represents (CR42)n whereby R4 represents a substituted or unsubstituted C1-8 alkyl group or a substituted or unsubstituted aryl group or a hydrogen atom and whereby n is from 0-20 and each R4 is the same or different;
OR2 represents the residue of an olfactive alcohol or of the enol form of an olfactive aldehyde or olfactive ketone;
is 0, 1 or 2; and
is 0, 1, 2 or 3. The compounds can be used in the manufacture of odorant compositions used in the preparation of cosmetic and laundry products.