通过动力学同位素效应(KIE)测量、中间体分离和密度泛函理论计算研究了(环戊二烯酮)铁羰基配合物催化胺脱氢的机理。(环戊二烯酮)铁胺中间体被分离并通过1 H 和13 C NMR 光谱以及 X 射线晶体学进行表征。分离的铁胺络合物非常稳定,并经过正式的β-氢化物消除,产生亚胺和氢化铁络合物。观察到的铁催化 4-甲氧基-N脱氢的 KIE-(4-甲基苄基)苯胺按照分步脱氢制得。密度泛函计算证实了一种逐步机制,涉及从胺到铁的决定速率的氢化物转移,产生金属氢化物和亚胺中间体,然后是质子从亚胺离子转移到环戊二烯酮配体的氧。
in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine‐functionalized Zr metal–organicframework (MOF), UiO‐66‐NH2 (Pt@UiO‐66‐NH2) as a multifunctional catalyst in the one‐pot tandem synthesis of nitrones
modern organic synthesis, chemoselectivity is recognized as an important factor in the development of new methodologies. Chemoselective nucleophilic addition to amide carbonyl centers is a challenge because classical methods require harsh reaction conditions to overcome the poor electrophilicity of the amide carbonyl group. We have successfully developed a reductive nucleophilic addition of mild nucleophiles
A low loading of a quinine-derived squaramide efficiently catalyzes the triple-domino Michael/aza-Henry/cyclization reaction between 1,3-dicarbonyl compounds, β-nitroolefins, and aldimines to provide tetrahydropyridines bearing three contiguous stereogenic centers in good yields, excellent enantiomeric excesses, and up to high diastereomeric ratios.
trans‐stereocomplementary synthetic manner. cis‐Selective cyclo‐condensation proceeded between 2‐sulfanylpropanoic acid (thiolactic acid) and an imine derived from 4‐bromobenzaldehyde and methylamine, whereas Ti(OiPr)4 and Ti(OiBu)4‐promoted trans‐selective cyclo‐condensation proceeded between benzyl 2‐sulfanylpropanoate and the imine. The obtained cis‐ and trans‐2‐(p‐bromophenyl)‐5‐methylthiazolidin‐4‐ones
新颖顺-和反式-2-(p溴苯基)-5- methylthiazolidin -4-酮,小号,Ñ含杂环化合物,是提供了一种在CIS -stereocomplementary和反式-stereocomplementary合成方式。顺式-选择性环缩合反应在2-硫烷基丙酸(硫代乳酸)与由4-溴苯甲醛和甲胺衍生的亚胺之间进行,而Ti(O i Pr)4和Ti(O i Bu)4则促进了反式-选择性环缩合反应。 2-磺硫基丙酸苄酯与亚胺之间的缩合反应。获得的顺式-和反式- 2-(p溴苯基)-5- methylthiazolidin -4-酮被成功地转换为利用铃木-宫浦和宫浦-石山横2-(3-呋喃基)苯基衍生物和双(频哪醇基)二硼烷衍生物偶联反应分别以增强作用方式进行。
Four-Electron Electrocyclic Ring-Opening/Intermolecular [4+2] Cycloadditions of α-Hydroxycyclobutenones: Stereoselective Synthesis of Multiple Substituted δ-Lactams
作者:Peidong Song、Qing Li、Congcong Wang、Wenfa Wu、Xu Mao、Jiajia Wang、Xiangdong Hu
DOI:10.1002/adsc.201501152
日期:2016.4.14
four‐electron electrocyclic ring‐opening/intermolecular [4+2] cycloaddition of α‐hydroxycyclobutenones is reported. The reaction represents the first example for the intermolecular cycloaddition of the extensively studied enol‐ketene intermediate, and provides a new synthetic route to multiply substituted δ‐lactams in high stereoselectivity.