Synthesis of Isoxazolidine by Tandem CuAAC/Ring Cleavage/5‐endo‐trig Cyclization

Abstract

Copper‐catalyzed transformations of oxime ethers and sulfonyl azides were carried out to efficiently afford isoxazolidine. The reaction involved the tandem CuAAC/ring cleavage/rare 5‐endo‐trig cyclization procedures under mild condition. This methodology appears quite flexible and offers a capacity to generate the 2‐vinyl isoxazolidine products.

Mild and efficient synthesis of benzothiazolopyrimidine derivativesviaCuAAC/ring cleavage/cyclization reaction

“…A possible reaction pathway for the formation of benzothiazolopyrimidine ( 4a ) from precursors 1a , 2a and 3a is shown in Scheme 3. As described in the literature, 12,13 the substrates 2a and 3a reacted in the presence of the copper( i ) catalyst to form the metallated triazole A through the CuAAC pathway. Then, the complex A underwent a ring-cleavage rearrangement, leading to a highly active intermediate N -sulfonyl α-acylketenimine B .…”

“…12 Our group has also applied the CuAAC/ring cleavage reaction to the construction of pyridines, fused heterocycles, coumarins, indoles and other N-heterocyclic compounds. 13 Accordingly, we here describe a mild and efficient synthesis of benzothiazolopyrimidine derivatives via CuAAC/ring cleavage reaction (Scheme 1d). This protocol encompasses stirring a three-component reaction of 2-aminebenzo[ d ]thiazoles, sulfonyl azides and terminal ynones.…”

An Oxidant-Free and Mild Strategy for Quinazolin-4(3H)-One Synthesis via CuAAC/Ring Cleavage Reaction

“…It has also been used for modifying the structure of natural products, drugs, and biological macromolecules [42][43][44]. Our group has delved into this area and utilized the CuAAC/ring cleavage reaction to synthesize pyridine derivates, fused heterocycles, coumarins, indoles, and other nitrogenated compounds [45][46][47][48][49].…”