稳定的三环氨基过氧化物可以通过 β,δ'-三酮、H 2 O 2和 NH 基团源(如氨水或铵盐)的无催化剂三组分缩合选择性组装。这个过程是可扩展的并且可以产生克数量的三环杂环,在一个分子中包含过氧化物、氮和氧循环。令人惊讶的是,尽管有多种替代反应路线,通过过氧化物、半缩醛、单过氧缩醛和过氧半缩醛官能团的平衡,这种复杂的三环分子仍然可以选择性地形成!该反应由 H 2 O 2的“立体电子挫折”引发并将热力学和动力学控制元素与在热力学控制条件下演化的各种单环、双环和三环结构相结合,直到它们达到由逆α效应产生的动力学壁,即立体电子罚分过氧碳鎓离子和相关过渡态的形成。在这些条件下,在三个不同的杂环在无环前体框架上组装和融合的阶段,反应在达到最热力学稳定的产物之前停止。
reactions such as Michael and aldol reactions in aqueous media and the H−D exchange reactions using deuterium oxide. For example, a 200-mmol-scale Michael reaction under triphasic conditions proceeded rapidly, with an extremely high turnover number of up to 260 400 and an excellent turnover frequency of 48 s-1. No vanadium leaching was detected during the above reactions, and the catalyst was readily recycled
Preparation of a microsized cerium chloride-based catalyst and its application in the Michael addition of β-diketones to vinyl ketones
作者:Alexander O. Terent'ev、Vera A. Vil'、Ivan A. Yaremenko、Oleg V. Bityukov、Dmitri O. Levitsky、Vladimir V. Chernyshev、Gennady I. Nikishin、Fabrice Fleury
DOI:10.1039/c3nj01454a
日期:——
evaporation of its alcoholic solutions. The way of the preparation of the cerium chloride-based catalyst plays a decisive role in its catalytic activity. This catalyst is efficient in the Michaeladdition of β-diketones to vinyl ketones giving β,δ-triketones.
Selective Synthesis of Cyclic Peroxides from Triketones and H<sub>2</sub>O<sub>2</sub>
作者:Alexander O. Terent’ev、Ivan A. Yaremenko、Vladimir V. Chernyshev、Valery M. Dembitsky、Gennady I. Nikishin
DOI:10.1021/jo202437r
日期:2012.2.17
despite the diversity of possible peroxidation pathways giving cyclic compounds and oligomers, the reaction proceeds with high selectivity and produces tricyclic peroxides via the monoperoxidation of the carbonyl groups in the β-positions and the transformation of the δ-carbonyl group into the acetal one. The syntheses are scaled up to tens of grams, and the resulting peroxides can be easily isolated from
基于β,δ-三酮与H 2 O 2的酸催化反应,提出了一种组装过氧化物,单过氧缩醛和乙缩醛部分的三环结构的方法。通过使用大量强酸(例如H 2 SO 4,HClO 4或HBF 4)进行反应,选择性生成三环化合物,产率从39%到90%。,它们既充当催化剂,又充当助溶剂。该反应与众不同之处在于,尽管提供环化合物和低聚物的可能的过氧化途径多种多样,但该反应仍以高选择性进行,并通过β位置上的羰基的单过氧化作用和δ-羰基的转化产生三环过氧化物。组成乙缩醛一个。合成物放大至数十克,并且可以容易地从反应混合物中分离出所得的过氧化物。
Nickel(II)-catalyzed Michael additions. Formation of quaternary centers and diastereoselective addition of enantiopure N -acetoacetyl-4-benzyloxazolidin-2-one
Ni(acac)2 and Ni(salicylaldehydate)2 are effective catalysts for conjugate additions of 2-methyl-1,3-dicarbonyl compounds to Michael acceptors. Significant diastereomeric excesses are obtained in the Michael additions of enantiopure N-acetoacetyl-4-benzyloxazolidinones. Reaction of the latter compound with aryl isocyanates affords unsymmetrical diamides of malonic acid.
Expanding the Scope of Lewis Acid Catalysis in Water: Remarkable Ligand Acceleration of Aqueous Ytterbium Triflate Catalyzed Michael Addition Reactions
作者:Rui Ding、Kambiz Katebzadeh、Lisa Roman、Karl-Erik Bergquist、Ulf M. Lindström
DOI:10.1021/jo051540n
日期:2006.1.1
Significant rate acceleration of metal-catalyzed Michaeladdition reactions in water was observed upon addition of small, dibasic ligands. Ytterbiumtriflate and TMEDA was the most effective combination leading to a nearly 20-fold faster reaction than in the absence of ligand.