PROCESS FOR THE SYNTHESIS OF KETONES FROM INTERNAL ALKENES
申请人:CALIFORNIA INSTITUTE OF TECHNOLOGY
公开号:US20140194604A1
公开(公告)日:2014-07-10
The present invention is directed to methods for oxidizing internal olefins to ketones. In various embodiments, each method comprising contacting an organic substrate, having an initial internal olefin, with a mixture of (a) a biscationic palladium salt; and (b) an oxidizing agent; dissolved or dispersed in a solvent system to form a reaction mixture, said solvent system comprising at least one C
2-6
carbon nitrile and optionally at least one secondary alkyl amide, said method conducted under conditions sufficient to convert at least 50 mol % of the initial internal olefin to a ketone, said ketone positioned on a carbon of the initial internal olefin. The transformation occurs at room temperature and shows wide substrate scope. Applications to the oxidation of seed oil derivatives and a bioactive natural product are described.
[(<i>p</i>-Cymene)RuCl<sub>2</sub>]<sub>2</sub>: An Efficient Catalyst for Highly Regioselective Allylic Alkylations of Chelated Amino Acid Ester Enolates
作者:Anton Bayer、Uli Kazmaier
DOI:10.1002/chem.201402825
日期:2014.8.11
are excellent nucleophiles for ruthenium‐catalyzedallylic alkylations. Although [Cp*Ru(MeCN)3]PF6 was found to be the most reactive catalyst investigated, with the resulting allyl complexes reacting at temperatures as low as −78 °C, unfortunately the process took place with only moderate regio‐ and diastereoselectivity. In contrast, [(p‐cymene)RuCl2]2 allowed allylations to be performed with a high degree
Highly Regioselective Ruthenium-Catalyzed Allylic Alkylations of Chelated Enolates
作者:Anton Bayer、Uli Kazmaier
DOI:10.1021/ol102106v
日期:2010.11.5
Ru-catalyzed allylicalkylations are a highly interesting alternative to Pd-catalyzed reactions. Ru complexes show a high tendency for regioretention, especially for branched and (Z)-configured substrates, and they do not undergo isomerization of the allyl intermediates formed. Therefore, (Z)-substrates conserve their olefin geometry, and a perfect chirality transfer is observed with optically active
alpha,beta-Disubstituted allylzincs with alkoxycarbonyl as the beta-substituent, generated via an umpolung of in situ generated pi-allylpalladium by transmetallation with diethylzinc, react with benzaldehyde at the most substituted allylic terminus to provide syn-gamma-butyrolactones 4 exclusively, while those with electron-donating Me, i-Pr, or OMOM as the beta-substituents react at both allylic termini to give mixtures of syn-2, anti-2 and Z-3. alpha,beta,gamma-Trisubstituted allylzincs provide Z,anti-adducts 5 exclusively. (C) 1998 Elsevier Science Ltd. All rights reserved.