We identified 2-phenylisophosphindoline 2-oxide as a suitable and potentially tunable catalyst for the catalytic Wittigreaction of aldehydes with activated organohalides. This catalyst was obtained by a straightforward two-step synthesis. Trimethoxysilane proved to be an efficient reducing agent for the in situ generation and regeneration of the catalyst from the corresponding phosphane oxide. Sodium
作者:Lukas Jedinak、LaToya Rush、Mijoon Lee、Dusan Hesek、Jed F. Fisher、Bill Boggess、Bruce C. Noll、Shahriar Mobashery
DOI:10.1021/jo401972a
日期:2013.12.6
nonstabilized phosphorus ylides with various carbonylcompounds in the presence of silver carbonate is reported. Wittig olefination of aromatic, heteroaromatic, and aliphatic aldehydes (yields >63%) and a ketone (yield 42%) are demonstrated. These reactions proceed overnight at room temperature, under weakly basic conditions, and as such extend the applicability of the Wittig reaction to base-sensitive
Catalytic Asymmetric Cyclopropanation of Allylic Alcohols with Titanium-TADDOLate: Scope of the Cyclopropanation Reaction
作者:André B. Charette、Carmela Molinaro、Christian Brochu
DOI:10.1021/ja0108382
日期:2001.12.1
titanium-TADDOLate complex was effective at catalyzing the cyclopropanation reaction of allylicalcohols in the presence 1 equiv of bis(iodomethyl)zinc. After initial optimization of the catalyst structure, excellent yields and enantiomeric ratios were obtained for 3-aryl- or 3-heteroaryl-substituted allylicalcohols (up to 97:3). Alkyl-substituted allylicalcohols gave modest yields and enantiomeric ratios (up
Scope and Limitation of the Microwave-Assisted Catalytic Wittig Reaction
作者:Marcel Hoffmann、Sunetra Deshmukh、Thomas Werner
DOI:10.1002/ejoc.201500310
日期:2015.7
We have developed a microwave-assisted catalyticWittigreaction. In this paper, we give full account of the scope and limitations of this reaction. A screening of various commercially available phosphine oxides as precatalysts revealed Bu3P=O to be the most promising candidate. We tested 10 silanes for the in situ reduction of the phosphine oxide to generate Bu3P as the actual catalyst. Different
我们开发了一种微波辅助催化 Wittig 反应。在本文中,我们充分考虑了该反应的范围和局限性。对各种市售氧化膦作为预催化剂的筛选表明,Bu3P=O 是最有希望的候选者。我们测试了 10 种硅烷原位还原氧化膦以生成 Bu3P 作为实际催化剂。测试不同的环氧化物作为掩蔽碱。在这方面,环己烯氧化物和丁烯氧化物被证明是合适的。该反应可在 125 °C 下进行,但在 150 °C 下可获得更高的产率和 E/Z 选择性。在优化的反应条件下,报道了各种醛类转化为相应烯烃的40多个实例。以高达 88% 的产率获得了具有高 E 选择性的产物。
Microwave-Assisted Synthesis of Phenylpropanoids and Coumarins: Total Synthesis of Osthol
A method was developed for the microwave-assisted one-pot synthesis of phenylpropanoids, monolignols, and coumarins. The chosen reaction conditions determine whether a cinnamic acid or coumarin derivative is produced. The optimized reaction conditions were also applied to the synthesis of osthol (13) and several other natural products.