TADDOL-based <i>P</i>,<i>S</i>-bidentate phosphoramidite ligands in palladium-catalyzed asymmetric allylic substitution
作者:Konstantin N. Gavrilov、Ilya V. Chuchelkin、Ilya D. Firsin、Valeria M. Trunina、Vladislav K. Gavrilov、Sergey V. Zheglov、Denis A. Fedorov、Victor A. Tafeenko、Ilya A. Zamilatskov、Vladislav S. Zimarev、Nataliya S. Goulioukina
DOI:10.1039/d3ob01891a
日期:——
phosphoramidites were synthesized. With respect to Pd(II), these ligands showed the ability to form stable P,S-chelate allylic complexes. The structures of the ligands and their complexes were confirmed by 2D NMR spectroscopy and single-crystal X-ray diffraction. These chiral inducers provided up to 99% ee in the Pd-catalyzed asymmetric allylic substitution of (E)-1,3-diphenylallyl acetate with C- and
合成了一系列易于制备的模块化手性P , S-二齿亚磷酰胺。对于Pd( II ),这些配体表现出形成稳定的P 、 S-螯合烯丙基配合物的能力。通过二维核磁共振波谱和单晶X射线衍射证实了配体及其配合物的结构。这些手性诱导剂在 Pd 催化的 ( E )-1,3-二苯基烯丙基乙酸酯与 C-和 N-亲核试剂的不对称烯丙基取代中提供高达 99% ee 的 ee ,在 Pd 介导的肉桂基烯丙基烷基化中提供高达 94% ee的反应β-酮酯和2,5-二甲基吡咯的酯。此外,在 2-(二乙氧基磷酰基)-1-苯基烯丙基乙酸酯和苯胺之间的罕见反应中,实现了高达 92% ee的定量转化率以及化学和区域选择性。讨论了结构参数、反应条件和配体与金属的比例对催化结果的影响。结果表明,配体在不同齿数上优于其类似物。
Formamide Synthesis through Borinic Acid Catalysed Transamidation under Mild Conditions
作者:Tharwat Mohy El Dine、David Evans、Jacques Rouden、Jérôme Blanchet
DOI:10.1002/chem.201600234
日期:2016.4.18
A highly efficient and mild transamidation of amides with amines co‐catalysed by borinic acid and acetic acid has been reported. A wide range of functionalised formamides was synthesized in excellent yields, including important chiral α‐amino acid derivatives, with minor racemisation being observed. Experiments suggested that the reaction rely on a cooperative catalysis involving an enhanced boron‐derived