Chemoselective technology

Enzymatic polymerizations are an emerging research area with not only enormous scientific and technological promise, but also a tremendous impact on environmental issues. Biocatalytic synthetic pathways are very attractive as they have many advantages, such as mild reaction conditions, high enantio-, regio- and chemoselectivity, and the use of nontoxic natural catalysts. 

Klempier, N., Harter, G., de Raadt, A. et al. 1996. Chemoselective hydrolysis of nitriles by Rhodococcus rhodochrous NCIMB 11216. Food Technology and Biotechnology, 34 67-70. 

The most useful technique is in situ racemization, allowing a second-order asymmetric transformation . However, chemoselectivity is required from a factor effecting a racemization in this case. This means that only the substrate must be racemized, and the chiral center of the product must remain intact. If this is impossible, then substrate and product must be separated before performing racemization of the remaining substrate. Economically, this is not a very attractive scheme. The second-order technology becomes especially elegant when racemization and crystallization steps are coupled together, because a substrate-prod-... 

R 766 M. Umeda and T. Tanaka, Application of MRS Technology to Diagnoses in Nervous System , Annual Review Shinkei, 2003,32 R 767 T. Wada and M. Sekine, A Novel Method for Oligonucleotide Synthesis on the Basis of Chemoselective Phospholynation , Yuki Gosei Kagaku Kyokaishi, 2003,61, 961... 

As listed in Table 2.1, biocatalytic technology employing either isolated enzymes or whole-cell biocatalysts is gaining popularity due to its superior chemoselectivity, regioselectivity, or stereoselectivity, as well as mild reaction conditions and environmental biocompatibility. 

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