A chemo-enzymatic oxidation/aldol sequential process directly converts arylbenzyl alcohols and cyclohexanol into chiral β-hydroxy carbonyls

• Published in: Green chemistry : an international journal and green chemistry resource : GC 2021-10, Vol.23 (19), p.7773-7779
• Main Authors: Wang, Yu, Wang, Chengyi, Cheng, Qipeng, Su, Yu, Li, Hongyu, Xiao, Rui, Tan, Chunxia, Liu, Guohua
• Format: Article
• Language: English
• Subjects: Alcohols; Aldehydes; Biological activity; Carbonyl compounds; Carbonyls; Catalysts; Cyclohexanol; Cyclohexanone; Deactivation; Enantiomers; Green chemistry; Intermediates; Ketones; Laccase; Oxidation; Proline; Steric hindrance
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d1gc02831f

The development of a combination enzyme and organocatalyst for aqueous sequential organic transformation has great significance, in that it is not only environmentally friendly but also overcomes only a single methodological drawback, either in the chemical or biological process. Herein, through the utilization of the bulky steric hindrance of chiral proline derivatives, an integrated laccase and proline as a chemo-enzymatic co-catalyst system is developed. It enables an efficient oxidation/aldol enantioselective sequential reaction to be accomplished, overcoming the mutual deactivation issue. As we present in this study, this one-pot organic transformation, an initial laccase-mediated oxidation of arylbenzyl alcohols and cyclohexanol to form aldehydes and cyclohexanone, followed by a subsequent proline derivative-catalyzed aldol condensation of the in situ generated intermediates, provides various 1,2-diastereoisomeric chiral β-hydroxy ketones with acceptable yields and high enantio -/diastereoselectivities. An integrated laccase and prolines as a co-catalyst system enables an efficient oxidation/Aldol process to direct access chiral β-hydroxy carbonyls by using alcohols instead of environmentally unfriendly aldehydes and ketones.