Flexible, phase-transfer catalyzed approaches to 4-substituted prolines.

A range of 4-substituted prolines can be rapidly synthesized from a protected glycine Schiff base in only four steps and in 27-55% overall yield. Phase transfer catalysis allows direct access to both enantiomeric series, and the relative stereochemistry at the 4-position is readily controlled (>10:1 dr) through the choice of hydrogenation conditions.

Synthesis and application of a new cleavable linker for "click"-based affinity chromatography.

A new chemically-cleavable linker has been synthesised for the affinity-independent elution of biomolecules by classical affinity chromatography. This azo-based linker is shown to couple efficiently with "click" derivatised ligands such as biotin propargyl amide through a copper(I)-catalysed Huisgen 1,3-dipolar cycloaddition reaction. Binding to Affi-Gel matrices displaying ligands coupled to the new linker is both efficient and selective.