Highly Enantioselective Cyanoformylation of Aldehydes Catalyzed by a Mononuclear Salen-Ti(OiPr)4 Complex Produced In Situ
作者:Shi-Kui Chen、Dan Peng、Hui Zhou、Li-Wei Wang、Fu-Xue Chen、Xiao-Ming Feng
DOI:10.1002/ejoc.200600795
日期:2007.2
An efficient enantioselective cyanoformylation of aldehydes with ethyl cyanoformate, catalyzed by a salen-Ti(OiPr)4 complex generated in situ, has been developed. Studies of nonlinear effects indicated that the mononuclear salen-titanium complex, and not a heterochiral complex, played a key role in the stereodiscriminating step of the reaction. During the preparation of the catalyst, the addition of
已经开发了醛与氰基甲酸乙酯的有效对映选择性氰基甲酰化,由原位生成的 salen-Ti(OiPr)4 配合物催化。非线性效应的研究表明,单核 salen-titanium 络合物,而不是异手性络合物,在反应的立体识别步骤中起关键作用。在催化剂的制备过程中,表明加入异丙醇可以避免形成杂手性配合物。在 5 mol-% 催化剂的存在下,该反应可以以极好的收率(高达 99%)和高对映选择性(高达 91% ee)进行。从初步研究中,已经提出了一种解释非对称归纳起源的过渡态。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)