Magnetic Superbasic Proton Sponges Are Readily Removed and Permit Direct Product Isolation
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- 作者：Elia M. Schneider ; Renzo A. Raso ; Corinne J. Hofer ; Martin Zeltner ; Robert D. Stettler ; Samuel C. Hess ; Robert N. Grass ; Wendelin J. Stark
- 刊名：Journal of Organic Chemistry
- 出版年：2014
- 出版时间：November 21, 2014
- 年：2014
- 卷：79
- 期：22
- 页码：10908-10915
- 全文大小：421K
- ISSN：1520-6904
文摘
Workup in organic synthesis can be very time-consuming, particularly when using reagents with both a solubility similar to that of the desired products and a tendency not to crystallize. In this respect, reactions involving organic bases would strongly benefit from a tremendously simplified separation process. Therefore, we synthesized a derivative of the superbasic proton sponge 1,8-bis(dimethylamino)naphthalene (DMAN) and covalently linked it to the strongest currently available nanomagnets based on carbon-coated cobalt metal nanoparticles. The immobilized magnetic superbase reagent was tested in Knoevenagel- and Claisen鈥揝chmidt-type condensations and showed conversions of up to 99%. High yields of up to 97% isolated product could be obtained by simple recrystallization without using column chromatography. Recycling the catalyst was simple and fast with an insignificant decrease in catalytic activity.