Novel developments in biocatalytic organic chemistry

In the last decade, modern synthetic organic chemistry has experienced an enormous progress in biocatalytic methodologies. Enzymatic routes and microbial whole-cell bioconversions have become a generally accepted synthetic tool. Recent advances in biocatalytic chemistry focus on unconventional non-protein biocatalysts such as catalytically active RNA-molecules, and biotransformations in ionic liquids. The example of ethyl 4-chloroacetoacetate depicts how whole-cell biocatalysis is developing from rather empirical screening studies towards a technology which selectively elucidates, engineers and employs living cells for bioconversions. This review further discusses the question whether there are natural Diels-Alderases, and gives an overview of novel and unconventional approaches in biodehalogenations and contrathermodynamic reactions. The biotechnological production of hydroquinone demonstrates that the efficiency of biocatalytic routes is not limited to stereoselective synthesis.