具有C2对称的双酰胺钛(Ⅳ)络合物催化二乙基锌与芳香醛不对称加成反应

摘要

Enantioselective addition of diethylzinc to a series of aromatic aldehydes was developed using a modular mandelic acid and 1,2-diaminocyclohexane-based chiralC2ligand(1S,2S)-N,N'-(a-hydroxy-(R)-phenyl)-acetamido-trans-l,2-diaminocy-clo-hexane(ld) with tetraisopropyl titanate( Ti (OiPr)4)complex. The catalytic system employing 15 mol% of Id with 120 mol% Ti(OiPr) 4 was found to promote the addition of diethylzinc ( ZnEt2 ) to a wide range of aromatic aldehydes with electron-donating and e-lectron-withdrawing substituents,giving up to 83% ee of the corresponding secondary alcohol under mild conditions.%一种手性环己基二胺和α-羟基苯乙酸制备的(1S,2S) -N,N’-(α-羟基-(R)-苯基)-乙酰氨基-反式-1,2-环己基二胺(1d)和( Ti(OiPr)4)络合物催化剂体系用于催化二乙基锌与系列芳香醛不对称加成反应.最佳的催化剂体系(15 mol％1d,120mo1％ Ti (OiPr)4),该催化剂能够对含有吸电子基团、供电子基团及不同位阻的芳香醛均有较好的效果,能够在较温和的条件下获得最高达83％ ee和中等的产率.