Epoxidation of olefins with a silica-supported peracid.
Anhydrous [2-percarboxyethyl] functionalized silica (2a) is an advantageous oxidant for performing the epoxidation of olefins 1. Epoxides 3 do not undergo the ring-opening reactions catalyzed by the acidic silica surface, except for particularly activated cases such as styrene oxide. The hydrophilic and acidic character of the silica surface does not interfere with the directing effects exerted by allylic H-bond acceptor substituents. The alkenes 1 carrying hydroxyl groups react with silica-supported peracid 2a faster than unsubstituted alkenes, thus reversing the trend known for reactions with soluble peracids. These results are attributed to the H-bond interactions of substrate 1 with the silanol and carboxylic acid groups bonded to the silica surface.
Departamento de Química Orgánica, Facultad de Farmacia, Universidad de Valencia, Avda. Vicente Andrés Estellés s.n., 46100-Burjassot, Valencia, Spain.
Rossella
R
Mello
Ana
A
Alcalde-Aragonés
María Elena
ME
González Núñez
Gregorio
G
Asensio
D000475:Alkenes / Q000737:chemistry*; D004852:Epoxy Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D012822:Silicon Dioxide / Q000737:chemistry*
D000475:Alkenes; D004852:Epoxy Compounds; D012822:Silicon Dioxide