A Remarkable Titanium-Catalyzed Asymmetric Strecker Reaction using Hydrogen Cyanide at Room Temperature
作者:Balamurugan Ramalingam、Abdul Majeed Seayad、Li Chuanzhao、Marc Garland、Kazuhiko Yoshinaga、Manabu Wadamoto、Takushi Nagata、Christina L. L. Chai
DOI:10.1002/adsc.201000462
日期:2010.9.10
Close to perfect enantioselectivity (up to 98% ee) is obtained for the formation of amino nitriles using hydrogen cyanide (HCN) as the cyanide source at room temperature for the first time. In an operationally simple process, the catalyst generated from a partially hydrolyzed titanium alkoxide (PHTA) and (S)‐N‐salicyl‐β‐amino alcohol ligand, catalyzes the cyanation of imines in a short reaction time
Highly Enantioselective Titanium-Catalyzed Cyanation of Imines at Room Temperature
作者:Abdul Majeed Seayad、Balamurugan Ramalingam、Kazuhiko Yoshinaga、Takushi Nagata、Christina L. L. Chai
DOI:10.1021/ol902540h
日期:2010.1.15
A highly active and enantioselective titanium-catalyzed cyanation of imines at roomtemperature is described. The catalyst used is a partially hydrolyzed titanium alkoxide (PHTA) precatalyst together with a readily available N-salicyl-β-aminoalcohol ligand. Up to 98% ee was obtained with quantitative yields in 15 min of reaction time using 5 mol % of the catalyst. Various N-protecting groups such as
Access to α-Arylglycines by Umpolung Carboxylation of Aromatic Imines with Carbon Dioxide
作者:Chun-Xiao Guo、Wen-Zhen Zhang、Hui Zhou、Ning Zhang、Xiao-Bing Lu
DOI:10.1002/chem.201604623
日期:2016.11.21
straightforward and transition‐metal‐free approach for the efficient synthesis of α‐arylglycine derivatives from aromatic imines and carbondioxide was enabled by an umpolung carboxylation reaction. Various substituted diphenylmethimines underwent the carboxylation smoothly with carbondioxide in the presence of potassium tert‐butoxide and 18‐crown‐6 to give the corresponding carboxylated products in good to high