BF₃·Et₂O-Catalyzed Formal [3 + 2] Reaction of Aziridinofullerenes with Carbonyl Compounds

Abstract

The BF3·Et2O-catalyzed formal [3 + 2] reaction of aziridinofullerenes with various carbonyl compounds for the easy preparation of fullerooxazolidines has been developed. Moreover, the reaction of aziridinofullerene with ethyl formate affords the simplest fullerooxazole without substituent.

Recent applications of aziridine ring expansion reactions in heterocyclic synthesis

“…In yet another recent report, Yang and coworkers have reported the BF 3 -OEt 2 -catalyzed cycloaddition of N-sulfonylaziridinofullerenes with various aromatic-, heteroaromatic-, and aliphatic aldehydes, and some ketones forming fullerooxazolidines. 94 The reaction of ethyl formate, however, led to elimination of ethoxy group in an unprecedented manner forming fullerooxazole bearing no substituent at C-2 position of oxazole ring. Scheme 54…”

Ring Expansions of Activated Aziridines and Azetidines

“…Minakata and co-workers reported Lewis base PCy 3 -catalyzed regioselective ring-expansion reaction of aziridinofullerenes 289 with CO 2 and aryl isocyanates via two consecutive nucleophilic substitution pathway (S N 2 0 or S N 2 00 ), producing oxazolidinofullerene and imidazolidinofullerene derivatives 290 in good yields [131]. Later, a BF 3 ·OEt 2 -catalyzed formal [3 + 2] cycloaddition reaction of aziridinofullerenes 289 with aldehydes and ketones was reported by Yang and Li for the synthesis of fullerooxazolidines 291 and fullerooxazole 292 in good yields (Scheme 74) [132].…”

Photoredox-Induced Functionalization of Alkenes for the Synthesis of Substituted Imidazolines and Oxazolidines

“…In general, 1,2-diamine and 1,2-amino alcohol, which are not easily available, can be smoothly transformed into the corresponding imidazoline and oxazolidine under harsh conditions, respectively. Besides, Lewis acid mediated [3 + 2] cycloaddition of N -tosylaziridines with nitriles or carbonyls, as an alternative approach, was applied to the syntheses of imidazolines or oxazolidines . However, N -tosylaziridines had to be synthesized from 1,2-amino alcohol .…”