Modified Shapiro Reactions with Bismesitylmagnesium As an Efficient Base Reagent
摘要:
Bismesitylmagnesium has been shown to successfully mediate the Shapiro reaction. A range of tosylhydrazones has been subjected to the developed system, which furnishes exceptionally high incorporation of the introduced electrophiles and good yields of the functionalized styrenes. At conveniently accessible temperatures and with a comparably small excess of base reagent, this protocol offers an efficient alternative to the lithium-mediated process. Importantly, 1.05 equiv of Welnreb amides are sufficient to obtain aryl enones in good yields.
Nonclassical Arylative Meyer–Schuster Rearrangement through Ni-Catalyzed Inner-Sphere Acyloxy Migration
作者:Jaehan Bae、Wooin Lee、Ho Seong Hwang、Seoyeon Kim、Jihee Kang、Naeem Iqbal、Eun Jin Cho
DOI:10.1021/acscatal.3c02374
日期:2023.8.18
A Ni(II)-catalyzed unconventional Meyer–Schuster rearrangement (MSR) is paired with cross-coupling through inner-sphere acyloxy migration. Various propargyl acetates react with aryl boronic acids, leading to the formation of a range of α-arylated enone derivatives. This transformation is enabled by the use of a P∧N-type phosphinooxazoline (PHOX) ligand, which allows the substrate to coordinate with
Ni(II) 催化的非常规迈耶-舒斯特重排 (MSR) 通过内球酰氧基迁移与交叉偶联配对。各种乙酸炔丙酯与芳基硼酸反应,形成一系列 α-芳基化烯酮衍生物。这种转变是通过使用 P ∧ N 型膦基恶唑啉 (PHOX) 配体实现的,该配体允许底物与方形平面 Ni(II) 中心配位。它引发炔部分的芳基镍化,然后进行乙酸基团的分子内转位。这种非经典方法允许在 α 位添加富电子亲核试剂,而不需要氧化还原添加剂。一系列对照实验包括18O同位素标记研究和计算分析证实了内球酰氧基迁移。