Copper- and Silver-Catalyzed Diastereo- and Enantioselective Conjugate Addition Reaction of 1-Pyrroline Esters to Nitroalkenes: Diastereoselectivity Switch by Chiral Metal Complexes
syn-Diastereoselective conjugateaddition of 1-pyrroline esters to nitroalkenes in good yields with an excellent enantioselectivity by using CuOAc/Me-FcPHOX catalyst in the presence of pyridine. In contrast, AgOAc/tBu-ThioClickFerrophos catalyzed the anti diastereoselective conjugateaddition with a high enantioselectivity without additional base. Thus, the preparation of chiral 1-pyrroline derivatives
顺-Diastereoselective共轭加成的1-吡咯啉酯以良好的收率具有优异的对映选择性硝基烯烃通过在吡啶的存在下使用CuOAc / ME-FcPHOX催化剂。相比之下,AgOAc / t Bu-ThioClickFerrophos催化了高非对映选择性的抗非对映选择性缀合物的添加,而没有额外的碱。因此,可以实现具有不同立体化学的手性1-吡咯啉衍生物的制备。共轭加合物中亚胺基的非对映选择性还原可得到2,5-顺-脯氨酸酯衍生物。