Chemo-enzymatic cascade reactions

Chemo-enzymatic cascade reactions

Chemo-enzymatic cascade reactions are one of the mainstays of the section Biocatalysis. By combining several steps in one pot a significant step economy can be realised and the potential for environmentally benign synthesis is improved. Thus several work up steps can be avoided and pure products are ideally isolated after a series of reactions in one single vessel after just one straightforward purification step. Immobilisation of homogenous catalysts and then combining them with enzymes (Scheme 1 & 2) were developed, many of them in collaboration with other research groups. 

Scheme 1: Enantioselective reductions combined with enantioselective hydrolyses to obtain highly pure chiral intermediates (Adv. Synth. Catal. 2006, 348, 471-475 and Top. Catal. 2006, 40, 35-44.).

Scheme 2: Immobilised TEMPO as organo-catalyst in the oxidation of a sensitive alcohol to aldehyde and subsequent enantioselective cyanide addition catalysed by a Hydroxynitrile lyase (Eur. J. Org. Chem. 2006, 1672–1677).

 

Today the focus is shifting to redox enzymes in combination with heterogeneous catalysts, such as Pd nanoparticles (Scheme 3). For this international collaborations as well as in house production of enzymes and chemo catalysts is utilised. In this manner a wide variety of compounds is assembled enantioselectively via concise routes in high purity.

 

Scheme 3: 3 step sequence for the synthesis of amino alcohol via alcohol dehydrogenase and Pd nanoparticle catalysed reactions (Green Chem. DOI: 10.1039/c3gc41666f).

 

For other sequences and synthesis routes please contact:  u.hanefeld@remove-this.tudelft.nl or f.hollmann@remove-this.tudelft.nl

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