姓名 Liu qi-bin
所在学校或单位 dalian
文章题目 Synthesis of chiral cyclohexane-backbone P,N-ligands derived from pyridine and their applications in asymmetric catalysis
期刊名 Tetrahedron Letters
年份,卷(期),起止页码 2007, 48(12), 2101-2104
影响因子 2.5
文章链接
http://www.sciencedirect.com/sci ... dcf59f699114d343343
Abstract
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 using 4 and asymmetric allylic alkylations with up to 95% ee using 5 and 93% ee using 4. Trans and cis P,N-ligands 4 and 5 all gave the product with the same configuration. It was suggested that the absolute configuration of the product was controlled by the configuration of the stereogenic pyridyl-bearing carbon of the ligands.
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