Iron(III) chloride/diorganyl diselenides: a tool for intramolecular cyclization of alkynone O-methyloximes.
This report describes the synthesis of 4-organoselenylisoxazoles via FeCl(3)/RSeSeR-mediated intramolecular cyclization of alkynone O-methyloximes. The optimized conditions allowed the cyclization to proceed at room temperature under ambient atmosphere, and the reaction requires a short time to be completed. The reaction conditions tolerated neutral, electron-donating and electron-withdrawing groups present in both substrates, alkynone O-methyloximes and diorganyl diselenides. Treatment of 4-organoselenylisoxazoles with n-butyllithium, followed by trapping with electrophiles, furnished the functionalized isoxazoles in good yields. The obtained products also proved to be suitable substrates for the preparation of 4-bromoisoxazoles via Br/Se exchange reaction.
Laboratório de Síntese, Reatividade, Avaliação Farmacológica e Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria-Rio Grande do Sul, 97105-900 Brazil.
Adriane
A
Sperança
Benhur
B
Godoi
Gilson
G
Zeni
D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D005290:Ferric Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D015394:Molecular Structure; D010091:Oximes / Q000737:chemistry*; D013237:Stereoisomerism
D000480:Alkynes; D005290:Ferric Compounds; D010091:Oximes; D007501:Iron