Zhang Qifeng, Liang Yuchen, Li Ruiqi, Huang Ziyi, Kong Lichun, Du Peng, Peng Bo
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University China
Chem Sci. 2022 Apr 9;13(18):5164-5170. doi: 10.1039/d2sc00476c. eCollection 2022 May 11.
The α-umpolung of carbonyl compounds significantly expands the boundaries of traditional carbonyl chemistry. Despite various umpolung methods available today, reversing the inherent reactivity of carbonyls still remains a substantial challenge. In this article, we report the first use of sulfonium salts, of well-established hypervalent iodines, for the carbonyl umpolung event. The protocol enables the incorporation of a wide variety of heteroatom nucleophiles into the α-carbon of 2-oxazolines. The success of this investigation hinges on the following factors: (1) the use of sulfoxides, which are abundant, structurally diverse and tunable, and easily accessible, ensures the identification of a superior oxidant namely phenoxathiin sulfoxide for the umpolung reaction; (2) the "assembly/deprotonation" protocol previously developed for rearrangement reactions in our laboratory was successfully applied here for the construction of α-umpoled 2-oxazolines.
羰基化合物的α-极性翻转显著拓展了传统羰基化学的边界。尽管如今有各种极性翻转方法，但扭转羰基固有的反应性仍然是一项重大挑战。在本文中，我们报道了首次使用硫鎓盐以及成熟的高价碘进行羰基极性翻转反应。该方案能够将多种杂原子亲核试剂引入2-恶唑啉的α-碳上。这项研究的成功取决于以下因素：（1）使用丰富、结构多样且可调节、易于获取的亚砜，确保了为极性翻转反应鉴定出一种优异的氧化剂即吩恶噻亚砜；（2）我们实验室先前为重排反应开发的“组装/去质子化”方案在此成功应用于构建α-极性翻转的2-恶唑啉。
