Modular chiral selenium-containing oxazolines: synthesis and application in the palladium-catalyzed asymmetric allylic alkylation
作者:Antonio L. Braga、Diogo S. Lüdtke、Jasquer A. Sehnem、Eduardo E. Alberto
DOI:10.1016/j.tet.2005.09.044
日期:2005.12
selenium-containing oxazolines has been synthesized from inexpensive and commercially available l-serine and l-aspartic acid. These new compounds were evaluated as chiral ligands in the palladium-catalyzedasymmetricallylicalkylation reaction, furnishing the product in high enantiomeric excess, using Cs2CO3/CH2Cl2 as the base/solvent system.
由廉价的和可商购的1-丝氨酸和1-天冬氨酸合成了一系列新的模块化的含手性硒的恶唑啉。这些新化合物在钯催化的不对称烯丙基烷基化反应中作为手性配体进行了评估,使用Cs 2 CO 3 / CH 2 Cl 2作为碱/溶剂体系提供了高对映体过量的产物。
Optically Active Iridium Imidazol-2-ylidene-oxazoline Complexes: Preparation and Use in Asymmetric Hydrogenation of Arylalkenes
作者:Marc C. Perry、Xiuhua Cui、Mark T. Powell、Duen-Ren Hou、Joseph H. Reibenspies、Kevin Burgess
DOI:10.1021/ja028142b
日期:2003.1.1
+89% enantiomeric excess); a transformation from one prevalent mechanism to another is inferred from this. The studies of pressure dependence revealed that many reactions proceeded with high conversions, and optimal enantioselectivities in approximately 2 h when only 1 bar of hydrogen was used. Deuterium-labeling experiments provide evidence for other types of competing mechanisms that lead to D-incorporation