A mild light-driven protocol for the direct alkylation of phenols is reported. The process is driven by the photochemical activity of a halogen-bonded complex formed upon complexation of the in situ generated electron-rich phenolate anion with the α-iodosulfone. The reaction proceeds rapidly (10 min) under microfluidic conditions, delivering a wide variety of ortho-alkylated products (27 examples,
NHC-Catalyzed Synthesis of α-Sulfonyl Ketones via Radical-Mediated Sulfonyl Methylation of Aldehydes
作者:Chaolei Liu、Zheng Liang、Ayisenbati Jialingbieke、Jian Gao、Ding Du
DOI:10.1021/acs.orglett.3c00734
日期:2023.4.21
An N-heterocyclic carbene (NHC)-catalyzed facile assembly of α-sulfonyl ketones has been successfully developed through a radical-mediated sulfonyl methylation of readily available aldehydes. This protocol involves the effective single-electron transfer reduction of α-iodosulfones by NHC-bound Breslow intermediates, thus allowing a subsequent radical–radical coupling to afford the target compounds
process is driven by the photochemical activity of halogen-bonded complexesformed upon complexation of a sacrificial donor, namely 1,4-diazabicyclo[2.2.2]octane (DABCO), with α-iodosulfones. The reaction provides a variety of densely functionalized products in good yields (up to 96% yield). Mechanistic investigations are reported. These studies provide convincing evidences for the photochemical formation
by the photochemical activity of allyl-functionalized phenolate anions, generated in situ upon deprotonation of the corresponding phenols. The reaction proceeds rapidly with reaction times as low as 35 min, delivering a wide range of densely functionalized products (20 examples, yields up to 69%). Mechanistic studies have also been performed providing convincing evidence for the photochemical formation