Annulative Aminosulfonylation of Unactivated Alkenes for Accessing Pyrazolines via Multicomponent SO2 Insertion
Zhenjie Qi1, Si-Miaomiao Wen2, Quansen Wu1
1Department of Engineering, Jining University, Qufu 273155, Shandong, China.
Abstract:
A direct arylsulfonylation of β,γ-unsaturated hydrazones method, in which sulfonated pyrazolines are accessed by a three-component reaction of β,γ-unsaturated hydrazones, DABSO, and aryldiazonium tetrafluoroborates, has been developed without external oxidants or catalysts. This transformation is triggered by the formation of arylsulfonyl radicals in situ from the reaction of aryldiazonium tetrafluoroborates and DABSO, and is enabled by controllable generation of C center radical, in which DABSO was utilized as the sulfone source and an oxidant in this radical-mediated cascaded reaction. A wide range of substrates can be applied in this process to afford pyrazolines in good yield, and it is amenable for gram-scale synthesis.
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