39877-86-6Relevant articles and documents
Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis inside a Self-Assembled Supramolecular Host
Catti, Lorenzo,Tiefenbacher, Konrad
, p. 14589 - 14592 (2018/01/27)
Carbonyl–olefin metathesis represents a powerful yet underdeveloped method for the formation of carbon–carbon bonds. So far, no Br?nsted acid based method for the catalytic carbonyl–olefin metathesis has been described. Herein, a cocatalytic system based on a simple Br?nsted acid (HCl) and a self-assembled supramolecular host is presented. The developed system compares well with the current benchmark catalyst for carbonyl–olefin metathesis in terms of substrate scope and yield of isolated product. Control experiments provide strong evidence that the reaction proceeds inside the cavity of the supramolecular host. A mechanistic probe indicates that a stepwise reaction mechanism is likely.
Synthesis of hexahydrocyclopenta[c]furans by an intramolecular iron-catalyzed ring expansion reaction
Hilt, Gerhard,Bolze, Patrick,Heitbaum, Maja,Hasse, Katrin,Harms, Klaus,Massa, Werner
, p. 2018 - 2026 (2008/09/17)
The intramolecular iron-catalyzed ring expansion reaction of epoxyalkenes was investigated with a preformed iron(salen) [Fe(Salen)] complex. The formal insertion of the alkene into the epoxide generated hexahydrocyclopenta[c]furan derivatives in moderate to good yields and diastereoselectivities depending on other functional groups present in the starting materials. In addition, oxygen-tethered epoxyalkenes were used for the synthesis of lignan isomers. The scope and limitations of the Fe (Salen)-catalyzed process of the reaction are discussed.
Stereoselective synthesis of δ-lactones from 5-oxoalkanals via one-pot sequential acetalization, tishchenko reaction, and lactonization by cooperative catalysis of samarium ion and mercaptan
Hsu,Fang
, p. 8573 - 8584 (2007/10/03)
By the synergistic catalysis of samarium ion and mercaptan, a series of 5-oxoalkanals was converted to (substituted) δ-lactones in efficient and stereoselective manners. This one-pot procedure comprises a sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reaction mechanism and stereochemistry are proposed and supported by some experimental evidence. Such samarium ion/mercaptan cocatalyzed reactions show the feature of remote control, which is applicable to the asymmetric synthesis of optically active δ-lactones. This study also demonstrates the synthesis of two insect pheromones, (2S,5R)-2-methylhexanolide and (R)-hexadecanolide, as examples of a new protocol for asymmetric reduction of long-chain aliphatic ketones.
