Reduction, of ketones, with

Reduction of ketones, with zinc powder and alcoholic sodium hydroxide leads to secondary alcohols, for example ... 

So far only two groups have reported details of the use of ionic liquids with wholecell systems (Entries 3 and 4) [31, 32]. In both cases, [BMIM][PF(3] was used in a two-phase system as substrate reservoir and/or for in situ removal of the product formed, thereby increasing the catalyst productivity. Scheme 8.3-1 shows the reduction of ketones with bakers yeast in the [BMIM][PF(3]/water system. 

Figure 8.2 Reduction of ketone with alcohol dehydrogenase from Thermoanaerobacter brockii using glucose-6-sulfate as a hydrogen source [3],...

Figure 8.6 Reduction of ketone with ruthenium complex and alcohol dehydrogenase using molecular hydrogen as a hydrogen source [5c],...

Figure 8.7 Reduction of ketone with photosynthetic biocatalyst using lightenergy [6b,c].

Figure 8.22 Reduction of ketone with anaerobic interface bioreactor [18b],...

Figure 8.23 Reduction of ketones with Geotrichum candidum in the presence of hydrophobic polymer XAD [19a],...

Figure 8.32 Reduction of ketones with reductase from baker s yeast [24].

Figure 8.35 Reduction of ketones with phenylacetaldehyde reductase from Corynebacterium strain ST-10 [26].

Introduction of an oxygen substituent at C-6 of a Hantzsch-type dihydropyridine having a sulfinyl group at C-5 affects the reduction of ketones with respect to both reactivity and stereoselectivity <96CC2535>. 

Scheme 9.3 Ir-catalysed reductions of ketones with aminosulfoxide ligand.

Scheme 9.18 Ru-catalysed reductions of ketones with (r 6-arene)-Af-perfluorosulfonyl-1,2-diamine and Af-(Af,Af-dialkylamino)sulfamoyl-l,2-diamine ligands.

Scheme 10.55 Borane reductions of ketones with p-hydroxy sulfoximine ligand.

Other S/N ligands have been investigated in the enantioselective catalytic reduction of ketones with borane. Thus, Mehler and Martens have reported the synthesis of sulfur-containing ligands based on the L-methionine skeleton and their subsequent application as new chiral catalysts for the borane reduction of ketones." The in situ formed chiral oxazaborolidine catalyst has been used in the reduction of aryl ketones, providing the corresponding alcohols in nearly quantitative yields and high enantioselectivities of up to 99% ee, as shown in Scheme 10.60. 

Scheme 10.60 Borane reductions of ketones with L-methionine-derived S/N ligand.

Scheme 10.65 Ga-catalysed borane reductions of ketones with MTBH2 ligand.

Nakamura, K., Yamanaka, R., Matsuda, T. and Harada, T. (2003) Recent developments in asymmetric reduction of ketones with biocatalysts. Tetrahedron Asymmetry, 14 (18), 2659—2681. 

Groeger, H., Chamouleau, F., Orologas, N. et al. (2006) Enantioselective reduction of ketones with designer cells at high substrate concentrations highly efficient access to functionalized optically active alcohols. Angewandte Chemie-Intemational Edition, 45 (34), 5677-5681. 

They were applied as effective reagents for the asymmetric reduction of ketones with borane. 

Certain catalysts promote the reduction of ketones with organosilanes. The reduction of acetophenone with Et3SiH is catalyzed by the diphosphine 65 and gives only a small amount of overreduction to ethylbenzene.377 Aryl alkyl enones and ynones are reduced to the corresponding alcohols with triethoxysilane and the titanium-based catalyst 66.378 Trichlorosilane reduces acetophenone in 90% yield with /V-formylpyrrolidinc catalysis.379... 

Chiral oxazaborolidines. Enantioselective reduction of ketones with a reagent prepared from BH, and the chiral vic-amino alcohol 1 (12,31) is now known to involve an oxazaborolidine. Thus BH3 and (S)-l, derived from valine, react rapidly in THF to form 2, m.p. 105-110°, which can serve as an efficient catalyst... 

Mechanism of Reduction of Ketones with Trialkylaluminum Reagents. 

The Meerwein-Ponndorf-Verley (MPV) reaction is an important route in the reduction of ketones with aluminum alkoxides (111). The mechanism has been... 

---