Amides,as nitrogen-containing compounds with unique physicochemical properties and biological activities,have demonstrated broad application prospects in fields such as medicine and materials.Particularly,compared with the vast majority of traditional amides in which the intramolecular p-π conjugation effects lead to a planar structure,the twisted amides,however,present distortions of the amide bond from planarity,thus resulting conformational and electronic modifications such as amide bond twist and nitrogen pyramidalization.The bond distortion of twisted amide is typically defined by the Winkler-Dunitz distortion parameters twist angle(τ)and pyramidalization parameters(XN).The former describes the magnitude of rotation around the N—C(O)bond while the later describes pyramidalization at nitrogen and pyramidalization at carbon.The values of τ=40° and XN=40° are considered as threshold values that allow for unique reactivity of the twist amide bond.This article introduces the unique structure and reactivity of these compounds,focusing on cyclic twisted amides and acyclic twisted amides,based on the range of T＞40° and XN＞40°.
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