Copper-catalyzed carbo-difluoromethylation of alkenes via radical relay.

Cai, Aijie; Yan, Wenhao; Zeng, Xiaojun; Zacate, Samson B; Chao, Tzu-Hsuan; Krause, Jeanette A; Cheng, Mu-Jeng; Liu, Wei · Nat Commun · 2021

basic_science · Level V

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Abstract

Organic molecules that contain alkyl-difluoromethyl moieties have received increased attention in medicinal chemistry, but their synthesis in a modular and late-stage fashion remains challenging. We report herein an efficient copper-catalyzed radical relay approach for the carbo-difluoromethylation of alkenes. This approach simultaneously introduces CF<sub>2</sub>H groups along with complex alkyl or aryl groups into alkenes with regioselectivity opposite to traditional CF<sub>2</sub>H radical addition. We demonstrate a broad substrate scope and a wide functional group compatibility. This scalable protocol is applied to the late-stage functionalization of complex molecules and the synthesis of CF<sub>2</sub>H analogues of bioactive molecules. Mechanistic studies and density functional theory calculations suggest a unique ligand effect on the reactivity of the Cu-CF<sub>2</sub>H species.