Aminocyclopentadienyl ruthenium complexes as racemization catalysts for dynamic kinetic resolution of secondary alcohols at ambient temperature
Aminocyclopentadienyl ruthenium complexes as racemization catalysts for dynamic kinetic resolution of secondary alcohols at ambient temperature
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DOI：
10.1021/jo0355799
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发表时间：
2004-03-19
影响因子：
3.6
通讯作者：
Park, JW
中科院分区：
文献类型：
--
作者：
Choi, JH;Choi, YK;Park, JW
氨基环戊二烯基。以环戊-2,4-二亚胺、Ru-3(CO)(12) 和 CHCl3 为原料合成了钌配合物，可用作仲醇动态动力学拆分 (DKR) 中脂肪酶的室温外消旋化催化剂：[2,3,4,5-Ph-4(eta(5)-C4CNHR)]Ru-(CO)(2)Cl (4: R = i-Pr; 5：R = n-Pr；6：R = t-Bu)、[2,5-Me-2-3,4-Ph-2(eta(5)-C4CNHR)]Ru(CO)(2)Cl (7：R = i-Pr；8：R = Ph) 和 [2,3,4,5-Ph-4(eta(5)-C4CNHAr)]Ru(CO)(2)Cl (9：Ar = p-NO2C6H4；10：Ar = p-ClC6H4；11：Ar = Ph；12：Ar = p-OMeC6H4；13：Ar = p-NMe2C6H4)。 (S)-4-苯基-2-丁醇外消旋化测试表明，7 是最活跃的催化剂，尽管 DKR 差异有所减小。配合物4用于多种醇的DKR；在室温下，不仅简单的醇，而且烯丙醇、炔醇、二醇、羟基酯和氯代醇等官能化醇均成功转化为手性乙酸酯。在催化外消旋化的机理研究中，氢化钌 14 似乎是一个关键物质。它是(S)-1-苯基乙醇与4和叔丁醇钾外消旋化过程中的主要有机金属物种。在另一个实验中，(S)-1-苯基乙醇在苯乙酮存在下被 14 催化外消旋化。
Aminocyclopentadienyl. ruthenium complexes, which can be used as room-temperature racemization catalysts with lipases in the dynamic kinetic resolution (DKR) of secondary alcohols, were synthesized from cyclopenta-2,4-dienimines, Ru-3(CO)(12), and CHCl3: [2,3,4,5-Ph-4(eta(5)-C4CNHR)]Ru-(CO)(2)Cl (4: R = i-Pr; 5: R = n-Pr; 6: R = t-Bu), [2,5-Me-2-3,4-Ph-2(eta(5)-C4CNHR)]Ru(CO)(2)Cl (7: R = i-Pr; 8: R = Ph), and [2,3,4,5-Ph-4(eta(5)-C4CNHAr)]Ru(CO)(2)Cl (9: Ar = p-NO2C6H4; 10: Ar = p-ClC6H4; 11: Ar = Ph; 12: Ar = p-OMeC6H4; 13: Ar = p-NMe2C6H4). The tests in the racemization of (S)-4-phenyl-2-butanol showed that 7 is the most active catalyst, although the difference decreased in the DKR. Complex 4 was used in the DKR of various alcohols; at room temperature, not only simple alcohols but also functionalized ones such as allylic alcohols, alkynyl alcohols, diols, hydroxyl esters, and chlorohydrins were successfully transformed to chiral acetates. In mechanistic studies for the catalytic racemization, ruthenium hydride 14 appeared to be a key species. It was the major organometallic species in the racemization of (S)-1-phenylethanol with 4 and potassium tertbutoxide. In a separate experiment, (S)-1-phenylethanol was racemized catalytically by 14 in the presence of acetophenone.