摘要：Delian Wei,JiaweiBu,ShengfuZhang,ShiyuChen, Ling Yue,XipanLi,KangjiangLiang*, andChengfengXia*

转自：康龙化成

Light-Driven Stepwise Reduction of Aliphatic Carboxylic Esters to Aldehydes and Alcohols

Delian Wei, Jiawei Bu, Shengfu Zhang, ShiyuChen, Ling Yue, Xipan Li, Kangjiang Liang*, and Chengfeng Xia*

Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy Yunnan University Kunming 650500, China.

—Angew. Chem. Int. Ed. 2025, 64,e202420084.

Recommended by Bingbing Chang_ MC5

KEY WORDS: photo chemistry, reduction of carboxylic esters (反应类型), Aliphatic carboxylic esters (原料),aldehydes, alcohols (产物), C (sp3)-H, C (sp2)-H (成键类型), DBPP, C12H25SH, prolinol (其他)

ABSTRACT: The reduction of carboxylic esters to aldehydes and alcohols is a fundamental functional group transformation in chemistry. However, the inertness of carbonyl group and the instability of ketyl radical anion intermediate impede the reduction of carboxylic esters via photochemical strategy. Herein, Chengfeng Xia et aldescribed the reduction of aliphatic carboxylic esters with synergistic dual photocatalysis via phenolate-catalyzed single electron transfer process and thiolcatalyzed hydrogen atom transfer process. The competitive back electron transfer process was effectively inhibited by protonation of the ketyl-type radical anion. This protocol enabled the efficient reduction of carboxylic esters to alcohols under mild conditions. By interruption of the reduction withprolinol, the step-controlled reduction of carboxylic esters to aldehydes was accomplished. The developed process was also successfully applied to the preparation of deuterated alcohols and aldehydes from esters with D2O as the deuterium source.

bstrate Scope of Photochemical Reduction of Aliphatic Carboxylic Esters to Alcohols

Step-Controlled Reduction of Aliphatic Carboxylic Esters to

Substrate Scope of Photochemical Reduction of Aliphatic Carboxylic Esters to Alcohols

Aldehydes

Reduction of Aliphatic Aldehydes and Ketones

In summary, the unactive aliphatic carboxylic esters were efficiently reduced by the synergistic action of a phenolatetype photocatalyst and a thiol catalyst via sequential SET/HAT processes. The competitive back electron transfer process that impeded the radical reduction of carboxylic esters was tactfully surmounted by protonation of the ketyl radical anion. The developed photochemical protocol enabled the reduction of diverse primary, secondary, and tertiary aliphatic carboxylic esters to alcohols in excellent yields. The step-controlled reduction of esters to aldehydes was accomplished with proline as additive for the in situ formation of reduction-resistant enamine/oxazolidine intermediate. This photochemical protocol was also successfully exploited in the preparation of deuterated alcohols and aldehydes.

来源：新浪财经