Synthetically amenable amide derivatives of tosylated-amino acids as organocatalysts for enantioselective allylation of aldehydes: computational rationale for enantioselectivity
作者:Debashis Ghosh、Debashis Sahu、S. Saravanan、Sayed H. R. Abdi、Bishwajit Ganguly、Noor-ul H. Khan、Rukhsana I. Kureshy、Hari C. Bajaj
DOI:10.1039/c3ob27513b
日期:——
A phenylalanine derived chiral amide is developed that serves as an effective organocatalyst for the reaction of allyltrichlorosilane with aryl, hetero-aryl and α,β-unsaturated aldehydes to afford the desired homoallylic alcohols in good yield (up to 90%) and high enantioselectivity (up to 99%). The experimental results and DFT calculations suggest that para substituted aromatic aldehydes as substrate show higher ee in the product than their ortho/meta counterparts. The 1H and 13C NMR spectra study corroborated the calculated results. The chiral organocatalyst can be easily synthesized from optically pure phenylalanine in two simple steps with 90% overall yield.
开发了一种由苯丙氨酸衍生的手性酰胺,它作为有效的有机催化剂,用于烯丙基三氯硅烷与芳基、杂芳基和α,β-不饱和醛的反应,以良好的产率(高达90%)和高对映选择性(高达99%)得到所需的同烯丙基醇。实验结果和DFT计算表明,与邻/间位取代的芳香醛相比,对位取代的芳香醛作为底物在产物中显示出更高的对映体过量值。1H和13C NMR光谱学研究证实了计算结果。手性有机催化剂可以通过两个简单步骤从光学纯苯丙氨酸轻松合成,总产率为90%。