Dauben–Michno oxidative transposition of allylic cyanohydrins — Enantiomeric switch of (–)-carvone to (+)-carvone*Based on the 2010 Bader Award Lecture.
for the synthesis of 0-substituted cyanohydrins from aldehydes and ketones, in the absence of solvent, employing minimum amounts of the corresponding cyanides has been optimised. Aldehydes react more rapidly than ketones using triethylamine as catalyst offering in both cases almost quantitative yields of the corresponding O-trimethylsilyl, O-methoxycarbonyl, O-benzoyl and O-acetyl cyanohydrins.
Allyl cyanides are found to add across alkynes in the presence of a nickel catalyst prepared from Ni(cod)2 and P(4-CF3-C6H4)3 in situ to give variously functionalized di- or trisubstituted acrylonitriles in highly stereoselective manners possibly via a pi-allylnickel species as an intermediate. alpha-Siloxyallyl cyanides also react at the gamma-position of a cyano group with both internal and terminal
show that commercially available nanoceria catalyzes the cyanosilylation of different ketones (21 examples) at temperatures between 0 and 50 °C, in high yields, under solventless conditions if required. The nanoceria network atoms act in a cooperative way to provide a bifunctional acid-base solid catalyst for the cyanosilylation reaction. The amorphization of nanoceria during reaction, due to acid release
Gold(III)-Catalyzed Cyanosilylation of Ketones and Aldehydes
作者:Insung Choi、Hee-Seung Lee、Woo Cho、Sung Kang、Amiya Medda、Jungkyu Lee
DOI:10.1055/s-2008-1032154
日期:2008.2
efficient catalyst for the cyanosilylation of various ketones and aldehydes. The reactions were complete within 30 minutes at room temperature in the presence of only one mol% gold(III) chloride, yielding the corresponding cyanohydrin trimethylsilyl ethers in very good yields. The isolated yields for the reactions of ketones were up to 98%, and the reactions of aldehydes gave 100% conversion, as monitored