Asymmetric Michael reaction of α-cyano carboxylates catalyzed by a rhodium complex with trans-chelating chiral diphosphine PhTRAP
作者:Masaya Sawamura、Hitoshi Hamashima、Yoshihiko Ito
DOI:10.1016/s0040-4020(01)89377-7
日期:1994.4
Asymmetric Michael reaction of 2-cyanopropionates with vinyl ketones or acrolein in the presence of 0.1–1 mol% of a rhodium catalyst prepared in situ from RhH(CO)(PPh3)3 and a trans-chelating chiral diphosphine ligand (S,S)-(R,R)-PhTRAP in benzene at 3–5°C gave optically active Michael adducts with high enantiomeric excesses (83–93% ee) in high yields. The reaction of 2-cyanopropionate with methacrolein
在0.1–1 mol%由RhH(CO)(PPh 3)3和反式螯合的手性二膦配体(S,S)-(R,R)-PhTRAP在3-5°C的苯中产生的光学活性迈克尔加合物具有很高的对映体过量率(83-93%ee),且收率很高。2-氰基丙酸酯与甲基丙烯醛和巴豆醛的反应进行得有些缓慢,得到中等对映选择性但低非对映选择性的非对映异构体混合物。2-氰基丁酸酯和2-氰基-3-甲基丁酸酯与丙烯醛的反应得到相应的迈克尔加合物,其对映体过量比2-氰基丙酸酯低得多。将来自丙烯醛的迈克尔加成产物转化为旋光性α-甲基-α-氨基酸。