Herein we present the first catalytic enantioselective Wittigreaction. Chiral mono- and diphosphines were employed as catalysts for the desymmetrization of a prochiral ketone. The reaction was performed under microwave dielectric heating as well as under conventional heating. Selected catalysts led to moderate to good yields and enantioselectivities. In the presence of (+)-1,2-bis[(2S,5S)-2,5-dim
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
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。
On the stereochemistry of the bis-nor-wieland-miescher ketome
作者:Barry M. Trost、Dennis P. Curran
DOI:10.1016/s0040-4039(01)92384-6
日期:1981.1
Catalytic Kinetic Resolution Reaction of (±)-5-Methylbicyclo[3.3.0]oct-1-ene-3,6-dione