Wacker-type oxidation of cyclopentene under dioxygen atmosphere catalyzed by Pd(OAc)2/NPMoV on activated carbon

1‐(Trifluoromethyl)cyclopent‐3‐enecarboxylic Acid Derivatives: Platforms for Bifunctional Cyclic Trifluoromethyl Building Blocks

“…Iodolactonization [16] of the cyclopentenecarboxylic acid 4 afforded the iodolactone 14 in 60 % isolated yield (monitoring of the reaction by 19 F NMR in the presence of an internal standard revealed the total conversion of 4 into 14, but a significant amount of the starting material was always recovered after workup). Iodolactone 14 is an interesting intermediate for creating molecular diversity through ringopening with various nucleophilic species.…”

“…control of the temperature was necessary to limit the formation of benzyl alcohol and a trifluoromethylated byproduct (detected in the 19 F NMR spectrum of the crude mixture but not isolated) during the hydroboration process. Apparently, the inductive effect of the trifluoromethyl group activates the ester reduction by BH 3 ·Me 2 S, which competes with the olefin hydroboration pathway.…”

“…Ishii and co-workers reported the conversion of cyclopentene into cyclopentanone under oxygen by using a catalytic system consisting of Pd(OAc) 2 and molybdovanadophosphate. [19] Their use in the reaction with cyclopentenecarboxylic acid 4 cleanly afforded the corresponding keto acid 18 in 85 % yield (Scheme 6). Unfortunately, no reaction was observed starting from the cyclopentene benzyl ester 12.…”

“…[27] Unfortunately, lactam 21 from the cyclocondensation of the major diastereomer c-20 (amino and carboxy groups in a cis relationship) was the only product that could be isolated (40 % yield). A complex mixture was detected in the aqueous layer by 19 F NMR, which probably results from the degradation of the amino acid t-20. Opening of lactam 21 under acidic conditions afforded the pure amino acid c-20 (Scheme 7).…”

Katalytische Oxidation von organischen Substraten durch molekularen Sauerstoff und Wasserstoffperoxid über einen mehrstufigen Elektronentransfer – ein biomimetischer Ansatz

“…[21] Das System besteht aus einem [41,42] Ishii et al berichteten unabhängig über ein ähnliches System zur allylischen Oxidation unter Einsatz eines Molybdovanadophosphats (NPMoV) und von Hydrochinon als ETMs (Schema 9); einige ausgewählte Beispiele sind in Tabelle 2 zusammengefasst. [43] Die Reaktivität des Multikatalysatorsystems war von der Ringgröße des Alkens abhängig: Während Cyclopenten und Cyclohexen nahezu quantitativ die entsprechenden Allylacetate lieferten, waren für größere [44] und zur Wacker-Oxidation von Cyclopenten, [45] terminalen Alkenen und Dienen. [46] Dieselben Autoren berichteten über die oxidative Carbomethoxylierung von Alkenen mit dem gleichen Katalysatorsystem (Pd/NPMoV) in einer Kohlenmonoxid/Luft-Atmosphäre und in Methanol als Lösungsmittel.…”