Asymmetric reduction by Geotrichum candidum

Other microorganisms have also been used for the asymmetric reduction of carbonyl compounds. Simple ahphatic ketones as well as aromatic ketones can be reduced with very high enantioselectivity by using biocatalysts. For example, aliphatic ketones such as 

2-pentanone, 2-butanone and 3-hexanone were reduced with excellent enantioselectivity to the corresponding (S)-alcohols by using the dried cells of G. candidum (Table 10.1). The dried-cell G. candidum system can distinguish between two alkyl groups with a difference of a single methylene imit in the reduction of 3-hexanone (Fig. 10.11). It has been applied to the reduction of aromatic ketones, and the substrate specificity of the system is shown in Table 10.2. For the reduction of trifluoromethyl ketone, the opposite enantiomers were obtained because different enzyme in the dried cell catalyzes the reaction. 

---

Figure 20 Use of IL as reaction medium for asymmetric reduction by Geotrichum candidum.

Matsuda T, Yamagishi Y, Koguchi S, Iwai N, Kitazume T. An effective method to use ionic liquids as reaction media for asymmetric reduction by Geotrichum candidum. Tetrahedron Lett. 2006 47 4619 1622. 

O Water absorbing polymer Figure 8.26 Asymmetric reduction of ketones in CO2 by Geotrichum candidum immobilized whole cell [20], (a) Time course for the reduction of o-fluoroacetophenone (b) substrate specificity (c) apparatus for C. candidum-cata yzed reduction with semiflow process using scC02. 

Rev. 42 (2013) 6213-6222. (d) L. Cao, F.v. Rantwijk, R.A. Sheldon, Cross-linked enzyme aggregates a simple and effective method for the immobilization of penicillin acylase, Org. Lett. 2 (2000) 1361-1364. (e) T. Matsuda, K. Nakayama, T. Abe, M. Mukouyama, Stabilization of pyruvate decarboxylase under pressurized carbon dioxide and water biphasic system, Biocatal. Bio-trans. 28 (2010) 167-171. (f)T. Matsuda, R. Marukado, M. Mukouyama, . Harada, K. Nakamura, Asymmetric reduction of ketones by Geotrichum candidum immobilization and application to reactions using supercritical carbon dioxide. Tetrahedron Asymm. 19 (2008) 2272-2275. 

Matsuda T, Marukado R, Mukouyama M, Harada T, Nakamura K. Asymmetric reduction of ketones by Geotrichum candidum immobilization and application to reaction using supercritical carbon dioxide. Tetrahedron Asymm. 2008 19 2272-2275. 

Nakamura, K, Matsuda, T Asymmetric reduction of ketones by the acetone powder of Geotrichum candidum. J. Org. Chem. 1998 63 8957-8964. 

---