Related Experiment Video
Updated: Aug 10, 2026

Light-driven Enzymatic Decarboxylation
Published on: May 22, 2016
Stereospecific Biohydroxylations of Protected Carboxylic Acids with Cunninghamella blakesleeana
Abstract:
Cunninghamella blakesleeana DSM 1906 was found to be an efficient biocatalyst for the biotransformation of cycloalkylcarboxylic acids into hydroxy and oxo derivatives. When cultivated in submerged culture, the fungus grew in pellets. In comparison with malt extract-glucose-peptone-yeast extract medium (medium E), Czapek-Dox medium was found to reduce pellet size. Cycloalkylcarboxylic acids were protected against microbial degradation by chemical transformation into 2-cycloalkyl-1,3-benzoxazoles. The transformations of protected cyclopentyl-, cyclohexyl-, cycloheptyl-, and cyclooctylcarboxylic acids by C. blakesleeana were investigated. The biotransformations were performed in medium E by using an aerated, stirred-tank bioreactor. The transformation of 2-cyclopentyl-1,3-benzoxazole yielded (1S,3S)-3-(benz-1,3-oxazol-2-yl)cyclopentan-1-ol as the main product. The main by-product was (1R)-3-(benz-1,3-oxazol-2-yl)cyclopentan-1-one, and 2-(benz-1,3-oxazol-2-yl)cyclopentan-1-ol was also obtained in small amounts. During the experiment, the enantiomeric excess of the main product increased up to 64%. 2-Cyclohexyl-1,3-benzoxazole was hydroxylated to 4-(benz-1,3-oxazol-2-yl)cyclohexan-1-ol. 2-Cycloheptyl-1,3-benzoxazole and 2-cyclooctyl-1,3-benzoxazole were transformed into several alcohols and ketones, all in low yields (2 to 19%).
Related Concept Videos
Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...
Esters to Carboxylic Acids: Saponification
The reaction requires a base in stoichiometric amounts, which participates in the reaction and is not regenerated later. So, the base acts as a...
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Carboxylic Acids to Esters: Acid-Catalyzed (Fischer) Esterification Overview
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Carboxylic Acids to Esters: Acid-Catalyzed (Fischer) Esterification Mechanism

