Asymmetric Diels–Alder reactions in supercritical carbon dioxide catalyzed by rare earth complexes
作者:Shin-ichi Fukuzawa、Ken Metoki、Shin-ichi Esumi
DOI:10.1016/j.tet.2003.04.009
日期:2003.12
The rare earth(III) salt catalysed asymmetric Diels–Alder reaction of cyclopentadiene with a chiral dienophile in supercritical carbon dioxide (scCO2) proceeded rapidly to give the adduct with a higher diastereoselectivity than that in dichloromethane; Yb(ClO4)3 gave the endo adduct with value up to 77% de at 40°C, 8 MPa. The chiral rare earth diketonate catalyzed hetero Diels–Alder reaction of the
稀土(III)盐催化的环戊二烯与手性双亲物在超临界二氧化碳(scCO 2)中的不对称Diels-Alder反应迅速进行,从而使加合物具有比二氯甲烷更高的非对映选择性。Yb(ClO 4)3在40℃,8 MPa下得到的内加合物的值高达de的77%。与二氯甲烷相比,Danishefsky's二烯与苯甲醛的手性稀土二酮酸酯催化的杂Diels-Alder反应在scCO 2中具有更高的收率和对映选择性。dium / pybox 8a3-丁烯酰基-2-恶唑烷酮的与MS4A的存在下环戊二烯配合物催化的不对称狄尔斯-阿尔德反应平稳地进行在SCCO 2,得到内型加合物10以高收率与高达88%的ee值。