Diastereoselective epoxidation of allylically substituted alkenes using metalloporphyrins as catalyst provides high trans-selectivities (i.e., trans-:cis-epoxide ratio). A diversity of cycloalkenes bearing different allylic substituents are shown to be efficiently epoxidized to afford the corresponding trans-epoxides with excellent trans-selectivities (up to >98%) and good yields (up to 99%). Acyclic allylic alkenes bearing different allylic substituents are efficiently epoxidized to afford the corresponding erythro-epoxides with good erythro-selectivities. The metalloporphyrin-catalyzed reactions exhibit up to 20 times higher trans-selectivities than the conventional method using m-chloroperoxybenzoic acid as oxidant.
使用
金属
卟啉作为催化剂的烯丙基取代烯烃的非对映选择性环氧化反应提供高选择性(即反式:顺式
环氧化物比)。显示出带有不同烯丙基取代基的多样环烯烃能够有效地环氧化,产生相应的反式
环氧化物,具有优异的反式选择性(高达>98%)和良好的产率(高达99%)。带有不同烯丙基取代基的无环烯丙基烯烃能够有效地环氧化,产生相应的顺式
环氧化物,具有良好的顺式选择性。
金属
卟啉催化的反应显示出比使用m-
氯过氧
苯甲酸作为氧化剂的传统方法高达20倍的反式选择性。