Satyanarayana Tummanapalli, Ferber Benoit, Kagan Henri B
Laboratoire de Catalyse Moléculaire (UMR 8182), Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud, 91405 Orsay, France.
Org Lett. 2007 Jan 18;9(2):251-3. doi: 10.1021/ol062653b.
A strong asymmetric amplification is observed in the addition of diethylzinc on aromatic aldehydes in the presence of the bistriflamide of trans-1,2-diaminocyclohexane 3a. The asymmetric amplification originates from the insolubility of the catalyst precursor 3a of low enantiomeric excess (ee), with a concomitant large increase of ee for the minor soluble part of 3a. Controlled mono-N-acetylation of 3a (20% ee) at -78 degrees C allowed isolation of 4 possessing 90% ee. [reaction: see text].
在反式-1,2-二氨基环己烷双三氟甲磺酰胺3a存在下，二乙基锌加成到芳香醛上时观察到强烈的不对称放大效应。这种不对称放大源于对映体过量（ee）较低的催化剂前体3a的不溶性，同时3a的少量可溶部分的ee大幅增加。在-78℃下对3a（ee为20%）进行可控的单-N-乙酰化反应，可分离得到ee为90%的4。[反应：见正文]
