在膦树状大分子配体存在下,使用氢在四氢呋喃中还原双(乙酰丙酮)钯[Pd(acac)2 ],形成树状大分子稳定的钯纳米颗粒。通过TEM,31 P NMR和31表征所得的Pd纳米颗粒P MAS NMR。结果表明,树枝状膦配体被氧化为氧化膦。这些树状聚合物稳定的Pd纳米颗粒被证明是Suzuki和Stille偶联反应和氢化的有效催化剂。树状楔用作稳定剂以防止纳米颗粒聚集,并且用作促进Pd催化剂的分离和/或再循环的载体。在铃木偶联反应的情况下,与常用的均相催化剂四(三苯基膦)钯[Pd(PPh 3)4相比,这些Pd纳米颗粒显示出高催化效率(TON高达65,000)和空气稳定性。]。此外,从庞大的树突状基质获得的结果表明,Pd纳米颗粒可能充当催化活性物质的储存库,并且该反应实际上是由从水中浸出的可溶性Pd(0)和/或Pd(II)物质催化的。纳米颗粒表面。
N-Heterocyclic carbene catalysed aerobic oxidation of aromatic aldehydes to aryl esters using boronic acids
作者:Panjab Arde、B. T. Ramanjaneyulu、Virsinha Reddy、Apurv Saxena、R. Vijaya Anand
DOI:10.1039/c1ob06566a
日期:——
The organocatalytic behavior of N-heterocyclic carbenes in the aerobicoxidation of aromatic aldehydes to esters with boronic acids has been explored. This transition metal-free protocol allows access to a wide variety of aromatic esters in good to excellent yields under mild reaction conditions.
Gold-Catalyzed C–O Cross-Coupling Reactions of Aryl Iodides with Silver Carboxylates
作者:Guifang Chen、Bo Xu
DOI:10.1021/acs.orglett.3c02254
日期:2023.9.1
We have developed a C–O cross-coupling reaction of (hetero)aryl iodides with silver carboxylates via a AuI/AuIII catalytic cycle. The transformation featured exclusive chemoselectivity and moisture/air insensitivity. Aromatic and aliphatic (including primary, secondary, and tertiary) silver carboxylates are all suitable substrates. Moreover, this protocol worked well intermolecularly and intramolecularly
我们开发了(杂)芳基碘化物与羧酸银通过 Au I /Au III催化循环进行的 C-O 交叉偶联反应。该转化具有独特的化学选择性和湿气/空气不敏感性。芳香族和脂肪族(包括伯、仲和叔)羧酸银都是合适的底物。此外,该方案在分子间和分子内均表现良好。最重要的是,无论底物的电子效应和空间位阻如何,都获得了良好的产率。