Catalytic Asymmetric Synthesis of O-Acetylcyanohydrins from Potassium Cyanide, Acetic Anhydride, and Aldehydes, Promoted by Chiral Salen Complexes of Titanium(IV) and Vanadium(V)
作者:Yuri N. Belokon、Paola Carta、Andrey V. Gutnov、Viktor Maleev、Margarita A. Moskalenko、Lidia V. Yashkina、Nicolai S. Ikonnikov、Nikolai V. Voskoboev、Viktor N. Khrustalev、Michael North
DOI:10.1002/1522-2675(200210)85:10<3301::aid-hlca3301>3.0.co;2-2
日期:2002.10
The utility of the chiral [Ti(μ-O)(salen)]2 complexes (R)- and (S)-1 (H2salen was prepared from (R,R)- or (S,S)-cyclohexane-1,2-diamine and 3,5-di(tert-butyl)-2-hydroxybenzaldehyde) as catalysts for the asymmetric addition of KCN and Ac2O to aldehydes to produce O-acetylcyanohydrins was investigated. It was shown that the complexes were active at a substrate/catalyst ratio of 100 : 1 and produced the
手性 [Ti(μ-O)(salen)]2 配合物 (R)- 和 (S)-1 (H2salen 由 (R,R)- 或 (S,S)-cyclohexane-1 制备,研究了 2-二胺和 3,5-二(叔丁基)-2-羟基苯甲醛)作为催化剂,将 KCN 和 Ac2O 不对称加成到醛中以生产 O-乙酰氰醇。结果表明,该配合物在底物/催化剂比率为 100:1 时具有活性,并在 -40° 时产生 ee 在 60-92% 范围内的 O-保护氰醇。其他配合物 [Ti2(AcO)2(μ-O)(salen)2] ((R)-4) 和 [Ti(CF3COO)2(salen)] ((R)-5) 由 (R) 制备)-1 用不同量的Ac2O 和(CF3CO)2O 处理,并在相同条件下测试它们的催化活性。发现(R)-4 的效率甚至高于(R)-1,而(R)-5 是无活性的。VIV和VV的相应Salen配合物的合成,[V(O)(salen)]