The Goldilocks Principle in Phase Labeling. Minimalist and Orthogonal Phase Tagging for Chromatography-Free Mitsunobu Reaction
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Updated: Feb 15, 2026

Orthogonal Protein Purification Facilitated by a Small Bispecific Affinity Tag
Published on: January 16, 2012
Mariann Szigeti1, Zoltán Dobi1, Tibor Soós1
1Institute of Organic Chemistry, Research Centre of Natural Sciences, Hungarian Academy of Sciences Magyar tudósok körútja 2, H-1117, Budapest, Hungary.
Abstract:
An inexpensive and chromatography-free Mitsunobu methodology has been developed using low molecular weight and orthogonally phase-tagged reagents, a tert-butyl-tagged highly apolar phosphine, and a water-soluble DIAD analogue. The byproduct of the Mitsunobu reactions can be removed by sequential liquid-liquid extractions using traditional solvents such as hexanes, MeOH, water, and EtOAc. Owing to the orthogonal phase labeling, the spent reagents can be regenerated. This new variant of the Mitsunobu reaction promises to provide an alternative and complementary solution for the well-known separation problem of the Mitsunobu reaction without having to resort to expensive, large molecular weight reagents and chromatography.
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