Stereoselective Synthesis of 4,5‐Dihydroisoxazole Derivatives from 1,1‐Dicyanocyclopropanes and Hydroxylamine Hydrochloride

Abstract

An efficient approach was developed for the synthesis of 4,5‐dihydroisoxazole derivatives from substituted 1,1‐dicyano‐cyclopropanes and hydroxylamine hydrochloride in ethanol through FeCl3‐catalyzed cascade addition reactions. This procedure gives a useful method to afford stereoselectively poly‐substituted 4,5‐dihydroisoxazoles in good yields.

Expanding Stereoelectronic Limits of endo-tet Cyclizations: Synthesis of Benz[b]azepines from Donor–Acceptor Cyclopropanes

“…These considerations suggest that both X and Z could be carbon atoms, with Z having an additional electron-withdrawing substituent. This design logically leads to donor–acceptor (DA) cyclopropanes , where both a pendant nucleophilic functionality and an acceptor group are attached at the same “anchor” carbon atom.…”

Acetic Acid-Catalyzed (3 + 2) Cyclization of 2-Aroyl-3-aryl-1,1-dicyanocyclopropanes with Arylhydrazines: To trans-4-Dicyanomethyl-1,3,5-triaryl-4,5-dihydropyrazoles

“…Research showed the obviously different reactivities and positions for D–A cyclopropanes with different electron-withdrawing groups. It is worth noting that a cyano group of these appositively dicyanocyclopropanes has preferable reactivity, which could participate in various types of reactions . Recently, the prominent pharmacological and physiological activities, and synthetic methodologies of appositively dicyanomethyl heterocycles have attracted much attention …”