Polar [3 + 2] cycloaddition of isatin-3-imines with electrophilically activated heteroaromatic N-ylides: Synthesis of spirocyclic imidazo[1,2-a]pyridine and isoquinoline derivatives

(3+2) Cycloaddition of Heteroaromatic N-Ylides with Sulfenes

A (3+2) cycloaddition of heteroaromatic N-ylides with sulfenes, which are generated in situ from sulfonyl chlorides, has been developed. A variety of ylides were transformed into the corresponding sulfone-embedded N-fused heterocycles in high yields. Hexafluoroisopropyl mesylate was demonstrated to be a suitable reactant for quinolinium ylides. Furthermore, this cycloaddition could be performed with an ylide prepared by a Cu-catalyzed ylide transfer reaction in a one-pot manner, extending the substrate scope to an unisolable ylide.

Recent synthetic strategies of spiro-azetidin-2-one, -pyrrolidine, -indol(one) and -pyran derivatives-a review

Spiro-heterocycles have received special attention in medicinal chemistry because of their promising biological activity. Over the years, many synthetic methodologies have been established for the construction of spirocyclic compounds. Spiro heterocycles such as spiro-azetidin-2-one, -pyrrolidine, -indol(one) and -pyran derivatives have been found to exhibit diversified biological and pharmacological activity in addition to their therapeutic properties. In view of these facts, we decided in this review to present representative synthetic approaches of the aforementioned spiro heterocycles, especially in the past 20 years.

Stereoselective synthesis of fused-, spiro- and bridged heterocycles via cyclization of isoquinolinium salts: A recent update

Isoquinoline and its derivatives are ubiquitous in natural alkaloids, synthetic materials and pharmaceuticals with broad spectrum of biological activities. In particular, isoquinolinium salts are important in organic synthesis because they...

The mechanism and diastereoselectivity in the formation of trifluoromethyl-containing spiro[pyrrolidin-3,2′-oxindole] by a catalyst-free and mutually activated [3+2]-cycloaddition reaction: a theoretical study

The mechanism and diastereoselectivity of the [3+2] cycloaddition reaction between (Z)-1-methyl-3-imino-indolin-2-one and 5-nitro-2-vinylpyridine with no catalyst in acetonitrile have been investigated by the DFT method and SMD solvation model.