title: Magnetic superbasic proton sponges are readily removed and permit direct product isolation.
abstract: 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-Schmidt-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.
authors.affiliation: Institute for Chemical and Bioengineering , Department of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli Strasse 10, CH-8093 Zurich, Switzerland.
authors.forename: Elia M
authors.initials: EM
authors.lastname: Schneider
authors.forename: Renzo A
authors.initials: RA
authors.lastname: Raso
authors.forename: Corinne J
authors.initials: CJ
authors.lastname: Hofer
authors.forename: Martin
authors.initials: M
authors.lastname: Zeltner
authors.forename: Robert D
authors.initials: RD
authors.lastname: Stettler
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Hess
authors.forename: Robert N
authors.initials: RN
authors.lastname: Grass
authors.forename: Wendelin J
authors.initials: WJ
authors.lastname: Stark
mesh_terms: D015057:1-Naphthylamine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry; D003460:Crystallization; D060328:Magnetic Phenomena; D053768:Metal Nanoparticles / Q000737:chemistry*; D011522:Protons; D059027:Recycling
chemical_list: D011522:Protons; D003035:Cobalt; C418992:1,8-bis(dimethylamino)naphthalene; D002244:Carbon; D015057:1-Naphthylamine