Tetrahedron report number 203

Herein we review recent advances in the asymmetric reduction of ketones by biocatalysts. Included are discussions on recent developments in methodologies to control enantioselectivities of catalytic reactions, and examples of practical applications that reduce various types of ketones are also shown.

Recent developments in asymmetric reduction of ketones with biocatalysts

Enzymes as Catalysts in Synthetic Organic Chemistry [New Synthetic Methods (53)]

(1985). Present and Future Applications of Lipases. Biotechnology and Genetic Engineering Reviews: Vol. 3, No. 1, pp. 193-218.

https://www.tandfonline.com/doi/pdf/10.1080/02648725.1985.10647813

Present and future applications of lipases

The development of novel biocatalytic methods is a continuously growing area of chemistry, microbiology, and genetic engineering due to the fact that biocatalysts are selective, easy-to-handle, and environmentally friendly. A wide range of reactions are catalyzed by microorganisms. Fungi can be considered as a promising source of new biocatalysts, mainly for chiral reactions. Chemo-, regio-, and stereoselective processes are very important in the synthesis of many chemical, pharmaceutical, and agrochemical intermediates; active pharmaceuticals; and food ingredients. This report reviews stereoselective reactions mediated by fungi, such as stereoselective hydroxylation, sulfoxidation, epoxidation, Baeyer–Villiger oxidation, deracemization, and stereo- and enantioselective reduction of ketones, published between 2000 and 2007.

Stereoselective biotransformations using fungi as biocatalysts

Asymmetric hydrolysis of (±)-1,2-diacetoxy-3-chloropropane (1) with a very small amount of a lipoprotein lipase gave (S)-1 of 90% enantiomeric excess (e.e.). Reactions of (S)-1 with phenols in an alkaline condition yielded the corresponding (S)-3-aryloxy-1,2-propanediols. From (S)-3-(1-naphthoxy)-1,2-propanediol (5) was synthesized the optically pure (S)-isomer of propranolol [1-isopropylamino-3-(1-naphthoxy)-2-propanol] (9), one of the ²-adrenergic blocking agents. Hydrolysis of (±)-1,2-diacetoxy-3-bromopropane (11) and (±)-1,2-diacetoxyethylbenzene (12) with the lipase afforded (S)-11 of 77% e.e. and (R)-12 of 73% e.e., respectively.

Asymmetric Hydrolysis of (±)-1,2-Diacetoxy-3-chloropropane and Its Related Compounds with Lipase. Synthesis of Optically Pure (S)-Propranolol

Microorganisms that hydrolyze methyl 2-phenylpropionate (1) or reduce 4-phenyl-2-butanone (3) were screened from 250 type cultures. Several Aspergilli and two bacteria hydrolyzed ester 1, and Asp. sojae IAM 2703 preferentially hydrolyzed (R)-isomer of (±)-1, whereas Bacillus subtilis var. niger IFO 3108 and Mycobacterium smegmatis ATCC 10143 preferentially hydrolyzed (S)-isomer. The hydrolysis of the related esters of 1 with these organisms was also examined.

Asymmetric Hydrolysis of (±)-α-Substituted Carboxylic Acid Esters with Microorganisms

α-Chlorination of Sulfoxides by Chlorine

Enzymes and microorganisms were screened for the enantioselective hydrolysis of (±)-1-acetoxy-2, 3-dichloropropane (1) which is convertible to epichlorohydrin. Pancreatin and steapsin from hog pancreas were found to hydrolyze (±)-1 asymmetrically to give (S)-1 of 90% enantiomeric excess (e.e.). From (S)-1 was synthesized the optically pure (S)-isomer of propranolol[1-isopropylamino-3-(1-naphthoxy)-2-propanol], one of the typical β-adrenergic blocking agents.

Shinobu Iriuchijima

Papers

Asymmetric Hydrolysis of (±)-1,2-Diacetoxy-3-chloropropane and Its Related Compounds with Lipase. Synthesis of Optically Pure (S)-Propranolol

Asymmetric Hydrolysis of (±)-α-Substituted Carboxylic Acid Esters with Microorganisms

α-Chlorination of Sulfoxides by Chlorine

Asymmetric hydrolysis of (.+-.)-1-acetoxy-2,3-dichloropropane with enzymes and microorganisms.

Chlorination of Sulfoxides with Sulfuryl Chloride