Bisoxazoline and Bioxazoline Chiral Ligands Bearing 4-Diphenylmethyl Shielding Substituents. Diels-Alder Reaction of Cyclopentadiene with 3-Acryloyl-2-oxazolidinone Catalyzed by the Aqua Nickel(II) Complex
4′-bis(diphenylmethyl)-2,2′-bioxazoline and 2,2′-isopropylidenebis(4-diphenylmethyloxazoline), and further to complexes with copper(II) trifluoromethanesulfonate and nickel(II) perchlorate hexahydrate. The nickel(II) aqua complex derived from the bisoxazoline effectively catalyzes the Diels-Alderreactions of cyclopentadiene with 3-acryloyl-2-oxazolidinone in high endo-selectivities and moderate enantioselectivities
Enantiopure 2-amino-3,3-diphenyl-1-propanol 已通过hidantoin 路线从二苯乙醛开始合成,然后通过手性 HPLC 进行后续的官能团转化和光学拆分。这种氨基醇可以转化为两个新的手性配体:4,4'-双(二苯基甲基)-2,2'-生物恶唑啉和 2,2'-异亚丙基双(4-二苯基甲基恶唑啉),并进一步与铜(II)复合三氟甲磺酸盐和高氯酸镍 (II) 六水合物。衍生自双恶唑啉的镍 (II) 水络合物通过方形平面过渡结构有效催化环戊二烯与 3-丙烯酰基-2-恶唑烷酮的狄尔斯-阿尔德反应,具有高内向选择性和中等对映选择性。
New Chiral Hydroxyoxazolines Based on Ketopinic Acid and Their Use in the Asymmetric Diels-Alder Reaction
Several chiral hydroxyoxazolines have been prepared starting from (1S)-(+)-ketopinic acid and enantiopure β-amino alcohols by short synthetic routes. They have been employed in the catalytic asymmetric Diels-Alder reaction, resulting in ee values of up to 90%.
Using chiral ionic liquid additives to enhance asymmetric induction in a Diels–Alder reaction
作者:P. Goodrich、H. Q. Nimal Gunaratne、L. Hall、Y. Wang、L. Jin、M. J. Muldoon、A. P. C. Ribeiro、A. J. L. Pombeiro、V. I. Pârvulescu、P. Davey、C. Hardacre
DOI:10.1039/c6dt04572c
日期:——
ligand has been complexed using Cu(II) and Zn(II) trifluoromethanesulfonate and a range of chiral ionicliquid (CIL) additives based on natural products were used as a co-catalyst for a Diels–Alderreaction. The catalytic performance of these systems was compared for the asymmetric Diels–Alderreaction between N-acryloyloxazolidinone and cyclopentadiene with and without the presence of a CIL additive
A new method for recycling chiral bis(oxazoline)-coppercomplexes is described based on the formation of charge-transfercomplexes, their subsequent precipitation, and reuse after addition of new substrates. The conditions to perform this procedure were optimized in the presence of three bis(oxazoline)-based ligands. When associated with copper salts, these ligands efficiently catalyzed the Diels-Alder
Recyclable Copper Catalysts Based on Imidazolium-Tagged Bis(oxazolines): A Marked Enhancement in Rate and Enantioselectivity for Diels–Alder Reactions in Ionic Liquid
作者:Simon Doherty、Peter Goodrich、Christopher Hardacre、Julian G. Knight、Mimi T. Nguyen、Vasile I. Pârvulescu、Cristina Paun
DOI:10.1002/adsc.200600531
日期:2007.4.2
Imidazolium-tagged bis(oxazolines) have been prepared and used as chiral ligands in the copper(II)-catalysed Diels–Alderreaction of N-acryloyl- and N-crotonoyloxazolidinones with cyclopentadiene and 1,3-cyclohexadiene in the ionic liquid 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [emim][NTf2]. A significant and substantial enhancement in the rate and enantioselectivity was achieved