Heredia Micaela D, Guerra Walter D, Barolo Silvia M, Fornasier Santiago J, Rossi Roberto A, Budén María E
INFIQC, Facultad de Ciencias Quı́micas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina.
J Org Chem. 2020 Nov 6;85(21):13481-13494. doi: 10.1021/acs.joc.0c01523. Epub 2020 Sep 23.
Novel approaches for N- and O-desulfonylation under room temperature (rt) and transition-metal-free conditions have been developed. The first methodology involves the transformation of a variety of -sulfonyl heterocycles and phenyl benzenesulfonates to the corresponding desulfonylated products in good to excellent yields using only KOBu in dimethyl sulfoxide (DMSO) at rt. Alternately, a visible light method has been used for deprotection of -methyl--arylsulfonamides with Hantzsch ester (HE) anion serving as the visible-light-absorbing reagent and electron and hydrogen atom donor to promote the desulfonylation reaction. The HE anion can be easily prepared by reaction of the corresponding HE with KOBu in DMSO at rt. Both protocols were further explored in terms of synthetic scope as well as mechanistic aspects to rationalize key features of desulfonylation processes. Furthermore, the HE anion induces reductive dehalogenation reaction of aryl halides under visible light irradiation.
已开发出在室温（rt）和无过渡金属条件下进行N-和O-脱磺酰化的新方法。第一种方法是在室温下仅使用叔丁醇钾（KOBu）在二甲基亚砜（DMSO）中，将各种磺酰基杂环和苯基苯磺酸盐转化为相应的脱磺酰化产物，产率良好至优异。另外，一种可见光方法已用于通过用汉斯酯（HE）阴离子作为可见光吸收试剂以及电子和氢原子供体来促进脱磺酰化反应，从而对α-甲基-α-芳基磺酰胺进行脱保护。HE阴离子可通过相应的HE与KOBu在室温下于DMSO中反应轻松制备。从合成范围以及机理方面对这两种方案进行了进一步探索，以阐明脱磺酰化过程的关键特征。此外，HE阴离子在可见光照射下会引发芳基卤化物的还原脱卤反应。
