asymmetric synthesis of 4H-chromenes starting from 2-alkyl-substituted phenols. The aerobic oxidation toward a transient ortho-quinone methide was efficiently catalyzed by a manganese(III) species MnL3 while the ensuing Michael addition of β-dicarbonyl compounds proved to be catalyzed by a chiral manganese phosphate MnL2X*.
的组合原位形成MNL 3复合物(HL = Hacac或R(C = O)CH 2 CO 2 R)和手性
磷酸HX *允许4的完全催化,不对称合成ħ -chromenes从2开始-烷基取代的
酚。
锰(III)物种MnL 3可以有效地催化向瞬态邻甲基
苯甲酸的好氧氧化,而随后的β-二羰基化合物的迈克尔加成反应则被手性
磷酸锰MnL 2 X *催化。