A p-toluenesulfonic acid catalyzed fluorination of α-branched ketones for the construction of fluorinated quaternary carbon centers has been developed, featuring a broad substrate scope, environmentally benign reaction conditions, and operational simplicity.
ReacTiO2ns for rings: Goldnanoparticles supported on TiO2 are used as a novel heterogeneous catalyst for the isomerization of epoxides to allylicalcohols by a concerted mechanism (see scheme). The reaction proceeds in high yields and the product selectivity is often remarkable.
作者:L. L. Frolova、L. V. Bezuglaya、I. N. Alekseev、P. A. Slepukhin、A. V. Kuchin
DOI:10.1007/s10600-014-0984-y
日期:2014.7
2α-Bromo,10β-pinanone-3 and 3α-bromo,10β-pinanone-4 were formed with 92–98% selectivity by bromination of isopinocamphone and cis-verbanone with Meldrum’s acid dibromide. 3α-Bromo, 10β-pinanone-4 was prepared for the first time. Its structure was confirmed by an XSA. Bromination of menthone by Meldrum’s acid dibromide formed mainly a mixture of diastereomeric 2-bromomenthones in a 2:1 ratio. Oxidative bromination of isopinocampheol by Ce(III)–LiBr–H2O2 caused rearrangement of the pinane structure into bornane and formed a mixture of 6-endo- and 6-exo-bromocamphor in a 5:1 ratio.
Asymmetric Synthesis of Oxygenated Monoterpenoids of Importance for Bark Beetle Ecology
作者:Suresh Ganji、Fredric G. Svensson、C. Rikard Unelius
DOI:10.1021/acs.jnatprod.0c00669
日期:2020.11.25
Herein we report the asymmetricsyntheses of a number of oxygenated terpenoids that are of importance in the chemical ecology of bark beetles. These are pinocamphones, isopinocamphones, pinocarvones, and 4-thujanols (= sabinene hydrates). The camphones were synthesized from isopinocampheol, the pinocarvones from β-pinene, and the thujanols from sabinene. The NMR spectroscopic data, specific rotations
Regioselektive und stereoselektive Addition von Formaldehyd an Monoterpenone
作者:Carl Heinz Brieskorn、Chung-Kyu Ryu
DOI:10.1002/ardp.19853180315
日期:——
Hydroxymethylderivate des Isopinocamphons, des Isocaranons, des Carvomenthons und des Menthons werden mit Formaldehyd unter alkalischer Katalyse hergestellt. Die bevorzugte Angriffsstelle des Formaldehyds ist das stärker alkylverzweigte C‐Atom des Enolats. Bei den beiden bicyclischen Monoterpenonen verläuft die Addition regio‐ und stereoselektiv, bei den beiden monocyclischen nur regioselektiv.