Aerobic Palladium‐Catalyzed Dioxygenation of Alkenes Enabled by Catalytic Nitrite

Abstract

Catalytic nitrite was found to enable carbon-oxygen bond-forming reductive elimination from unstable alkyl palladium intermediates, providing dioxygenated products from alkenes. A variety of functional groups are tolerated and high yields (up to 94%) are observed with many substrates, including a multi-gram scale reaction. Nitrogen dioxide, which could form from nitrite under the reaction conditions, was shown to be kinetically competent in the dioxygenation of alkenes. Furthermore, the reductive elimination event was probed with 18 O-labeling experiments, which demonstrated that both oxygen atoms in the difunctionalized products are derived from one molecule of acetic acid.

Redoxaktive NOx‐Liganden in palladiumvermittelten Prozessen

“…Bemerkenswerterweise ähnelt die Art der Pd-Cu-Spezies,d ie als aktive Spezies in dieser Chemie vorgeschlagen wurden, den vorgeschlagenen bimetallischen Pd-Cu-Spezies in der Sonogashira-Kreuzkupplung nach Va sella et al [32] Ende 2014 berichtete Grubbs über die aerobe Pd-katalysierte Dioxygenierung von Alkenen 30 zu den diacetoxylierten Produkten 31,a nd er katalytische Nitritanionen beteiligt sind (Schema 16). [33] …”

Palladium-Catalyzed Aerobic Intramolecular Aminoacetoxylation of Alkenes Enabled by Catalytic Nitrate

“…9 Very recently, the Grubbs group reported a palladium-catalyzed aerobic alkene diacetoxylation method mediated by a catalytic amount of silver nitrite (Scheme 2B). 10 We reasoned that a palladium-catalyzed aerobic aminooxygenation reaction might be possible using this electron transfer mediator strategy, as an NO x species could be a kinetically suitable mediator in the aerobic oxidation of the alkylpalladium(II) intermediate formed after aminopalladation.…”

“…10 We were delighted to find that the desired cyclization product 2a was indeed formed on the first attempt, albeit in only 11% yield. In order to optimize the reaction, we altered the components of the solvent mixture and observed a substantial boost in yield by removing MeNO 2 as co-solvent (entry 2).…”

“…The source of additional oxygen atoms in the product is not verified, but a previous 18 O labeling study showed that the oxygen came from the AcOH solvent. 10 Although the role of copper still remains elusive, the presence of copper is clearly advantageous as a decrease in yield was observed when no source of Cu was added. 13 The other necessary solvent component, Ac 2 O, could possibly sequester H 2 O generated in the catalytic system.…”

Palladium-Catalyzed Intermolecular Carboesterification of Alkynoic Acids with Alkenes

“…[2] 、双胺化反应 [3] 、双酯化反应 [4] 、双 羟化反应 [5] 、碳酯化反应 [6] 、碳胺化反应 [7] 等. 通常, 该 类反应需要用强氧化剂比如高价碘试剂 [8] 、过二硫酸 盐 [9] 、有机 F＋试剂 [10] 、过氧乙酸 [11] 等将二价的烷基钯 中间体氧化到更加贫电子的四价钯中间体, 进而通过还 原消除得到双官能团化产物.…”