Synthesis of chiral cyclohexane-backbone P,N-ligands derived from pyridine and their applications in asymmetric catalysis
作者:Qi-Bin Liu、Yong-Gui Zhou
DOI:10.1016/j.tetlet.2007.01.123
日期:2007.3
P,N-ligands trans-4 and cis-5 with a cyclohexane backbone were easily synthesized. The key step was chiral resolution of (±)-trans-2-pyridylcyclohexanols with DBTA. Enantiopure trans isomer was subjected to Mitsunobu reaction and deprotection to give the corresponding cis isomer. These ligands have been successfully used in asymmetric hydrogenation of arylalkenes with up to 93% ee using 5 and 90% ee