The sulfinylation reaction of aromatic and hetero-aromatic compounds with sulfinic esters as electrophiles has been investigated in different ionic liquids and by means of different Lewis acid salts in order to get moderate to good yields of asymmetrical sulfoxides. Mixtures of 1-butyl-3-methylimidazolium chloride and aluminum chloride were found to be the most efficient and recyclable reaction framework
Methyl Sulfinates as Electrophiles in Friedel–Crafts Reactions. Synthesis of Aryl Sulfoxides
作者:Francisco Yuste、Angélica Hernández Linares、Virginia M. Mastranzo、Benjamín Ortiz、Rubén Sánchez-Obregón、Alberto Fraile、José Luis García Ruano
DOI:10.1021/jo2006335
日期:2011.6.3
The Friedel-Crafts reaction of methyl alkyl-and arylsulfinates with aromatic systems, activated by one or more electron-donating substituents (OH, OMe, NFIR, NR2), provides alkyl aryl and diaryl sulfoxides under mild conditions and in moderate to good yields. The very high regioselectivity usually observed in these sulfinylation reactions is rationalized on the basis of a Wheland intermediate having a trigonal bypyramidal structure in which steric and electronic interactions are significant factors strongly destabilizing the attack to the ortho positions.