Epoxidation of (E,E)-Cinnamylideneacetophenones Using Salen Mn(III) as Catalyst

• Main Author: Santos, Clementina M.M.
• Publication Date: 2006
• Other Authors: Silva, Artur, Cavaleiro, José, Patonay, Támas, Lévai, Albert
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10198/3978
• topic: Cinnamylideneacetophenones; Salen catalyst; Epoxidation; Iodosylbenzene; Hydrogen peroxide; NMR spectroscopy

Salen Mn(III) complexes are efficient and practical catalysts for the epoxidation of various α,β-unsaturated carbonyl compounds. Among common oxidants used are iodosylbenzene, sodium hipochlorite, oxone, peracids and dimethyldioxirane [1]. Although the epoxidation of cinnamylideneacetophenones have already been reported in literature (by Julia’s epoxidation using hydrogen peroxide as oxidant [2] and by oxidation with dimethyldioxirane [3]), no studies were performed using these kind of salen Mn(III) complexes as catalysts. On these basis, we developed a study on the epoxidation of cinnamylideneacetophenones 1, catalyzed by commercially available Jacobsen’s catalyst [salen Mn(III)] and using iodosylbenzene and hydrogen peroxide as oxidants. Several experimental conditions have been used and the γ,δ-monoepoxides 2 and, in same cases, the diasteriomeric mixture of α,β:γ,δ-diepoxides 3 have been obtained. In this communication, we report the synthetic details and structural characterisation of the mono 2 and diepoxides 3 obtained.