Helical-Peptide-Catalyzed Enantioselective Michael Addition Reactions and Their Mechanistic Insights
作者:Atsushi Ueda、Tomohiro Umeno、Mitsunobu Doi、Kengo Akagawa、Kazuaki Kudo、Masakazu Tanaka
DOI:10.1021/acs.joc.6b00982
日期:2016.8.5
Helical peptide foldamer catalyzed Michael addition reactions of nitroalkane or dialkyl malonate to α,β-unsaturated ketones are reported along with the mechanistic considerations of the enantio-induction. A wide variety of α,β-unsaturated ketones, including β-aryl, β-alkyl enones, and cyclic enones, were found to be catalyzed by the helical peptide to give Michael adducts with high enantioselectivities
报道了螺旋肽折叠剂催化硝基烷或丙二酸二烷基酯与α,β-不饱和酮的迈克尔加成反应,以及对映体诱导的机理考虑。发现各种α,β-不饱和酮,包括β-芳基,β-烷基烯酮和环状烯酮,都可以被螺旋肽催化,从而得到具有高对映选择性(高达99%)的迈克尔加合物。根据X射线晶体学分析和depsipeptide研究,α-螺旋肽催化剂N端的酰胺质子N(2)–H和N(3)–H对激活迈克尔供体至关重要,而N-末端伯胺通过亚胺离子中间体的形成激活了迈克尔受体。