摘要
以价廉易得的天然金鸡纳生物碱奎宁和辛可宁为原料,在温和条件下容易地合成了6种手性双胺配体. 考察了它们与过渡金属Ir和Rh形成的配合物在苯乙酮不对称氢转移反应中的催化活性和不对称诱导作用. 结果表明, 9-氨基金鸡纳生物碱配体具有良好的不对称催化活性,而当配体中的氨基被取代后其对映选择性降低. 将9-氨基（9-脱氧）表辛可宁的Ir配合物用于其它芳香酮的不对称氢转移反应时,该配体也显示了很高的催化活性（80%～90%收率）和对映选择性（除对氯苯乙酮ee值为72%外,其余芳香酮ee值均为95%～97%）.
The asymmetric transfer hydrogenation using 2-propanol as the hydrogen source is a practical and versatile method for obtaining secondary alcohols because of the inexpensive reagents and operational simplicity. Six chiral diamine ligands were synthesized from natural Cinchona alkaloids, quinine and cinchonine, under mild conditions. These were first tested by asymmetric transfer hydrogenation of acetophenone in iridium and rhodium catalytic systems using 2-propanol as the hydrogen source. Both the iridium and rhodium complexes of these ligands showed high activity for this reaction, and the enantioselectivity was influenced deeply by the structure of the chiral ligands. The complexes of 9-amino（9-deoxy）epiquinine and 9-amino（9-deoxy）epicinchonine proved to be effective catalysts, whereas their benzamides and 4-chlorobenzamides provided only moderate ee. The Ircomplex of 9-amino（9-deoxy）epicinchonine was also applied in the hydrogenation of seven aromatic ketone substrates, resulting in a high catalytic activity （80 % N 90 % ） and high enantioselectivity （95 % - 97 % ee, except 72% ee for 4-chloroacetophenone）. This is the first case using Cinchona alkaloids skeleton in the iridium catalyzed asymmetric reactions.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2006年第6期527-531,共5页
基金
国家自然科学基金(20572131)
陕西省自然科学基金(2003B20)资助项目
关键词
金鸡纳生物碱
奎宁
辛可宁
手性双胺配体
手性催化剂
不对称氢转移反应
苯乙酮
Cinchona alkaloid
quinine
cinchonine
chiral diamine ligand
chiral catalyst
asymmetric transfer hydrogenation
acetophenone
