Jan Tois

Asymmetric Organocatalytic Diels-Alder Reactions on Solid Support

Asymmetric organocatalysis on solid support combines the environmental advantages of metal-free catalysts and the ease of operation of solid-supported reagents. Enantioselective organocatalytic DielsAlder reactions have been demonstrated by two different solid-supported chiral organocatalysts. The catalysts are easy to recover and they can be reused. The reactivity of the catalyst can be tuned by changing the solid support.

Synthetic Approaches towards Indoles on Solid phase - Recent Advances and Future Directions

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Solid-phase lithiation of 5-carboxyindoles

Direct functionalization of protected 5-carboxyindole by metalation has been performed for the first time on solid-phase. The indole moiety has been tethered to aminomethylated polytetrahydrofuran cross-linked polystyrene, forming a secondary amide, which functions as a directing metalation group. The ortho-lithiated species have been quenched with substituted benzaldehydes affording resin bound alcohols. After cyclative cleavage regioisomeric mixtures of phthalides were obtained in the ratio 80:20.

Solid-phase Bromination and Suzuki Coupling of 2-Carboxyindoles

As part of an ongoing lead discovery project we have developed a convenient method for the modification and substitution of indole moieties at the 3-position. Selective bromination of three different 2-carboxyindoles was followed by Suzuki cross-coupling with aryl and heteroaryl boronic acids on a Merrifield resin solid-phase. After column chromatography, yields of the 3- substituted indoles ranged from 42-98%.

A new application for PyOX-ligands: The asymmetric Henry reaction

C2-dissymmetric PyOX-ligands have been applied to the asymmetric Henry reaction. This widely applicable reaction is easy to perform, requires no inert atmospheres or dry solvents, and gives good selectivities. By adjusting ligand side-chains, a significant impact on selectivities was observed.

Mild and Efficient Synthesis of 2‐Indole‐2′‐oxazolines at Room Temperature—A Simple Access to Novel IndOX Ligands

Abstract A simple synthesis of a totally new enantiopure compound family, the IndOX compounds, is presented. These chiral compounds can be prepared in two simple steps from commercial starting materials, using no protective groups. The motive for preparing this family is the promising ligand activity of the already known analogs and structural similarity to active pharmaceuticals.