Wang Ye, Xiong Guowei, Zhang Chuanxin, Chen Yunfeng
School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430205, P. R. China.
J Org Chem. 2021 Mar 5;86(5):4018-4026. doi: 10.1021/acs.joc.0c02869. Epub 2021 Feb 15.
The regiospecific radical reactions of β-alkyl nitroalkenes with sulfonyl hydrazides depended to a great extent on the choice of a solvent and catalyst. In the presence of dimethylformamide (DMF), β-alkyl nitroalkenes more likely converted into electron-rich allyl nitro compounds, which reacted with sulfonyl hydrazides to afford allyl sulfones with high regioselectivity. While in acetonitrile (CHCN), vinyl sulfones were obtained directly sulfonation of electron-deficient β-alkyl nitroalkenes. The mechanism investigation revealed that the regioselectivity was controlled by the equilibrium of β-alkyl nitroalkenes and allyl nitro compounds.
β-烷基硝基烯烃与磺酰肼的区域特异性自由基反应在很大程度上取决于溶剂和催化剂的选择。在二甲基甲酰胺（DMF）存在下，β-烷基硝基烯烃更易转化为富电子的烯丙基硝基化合物，该化合物与磺酰肼反应可高区域选择性地生成烯丙基砜。而在乙腈（CHCN）中，缺电子的β-烷基硝基烯烃直接发生磺化反应生成乙烯基砜。机理研究表明，区域选择性受β-烷基硝基烯烃与烯丙基硝基化合物平衡的控制。
