Université de Haute-Alsace, Université de Strasbourg, CNRS, LIMA, UMR 7042, 68000 Mulhouse, France.
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
J Am Chem Soc. 2020 Jun 24;142(25):11153-11164. doi: 10.1021/jacs.0c03556. Epub 2020 Jun 11.
Ynamides are fascinating small molecules with complementary reactivities under radical, ionic, and metal-catalyzed conditions. We report herein synthetic and DFT investigations of palladium-catalyzed ligand-controlled regiodivergent hydrometalation reactions of ynamides. Germylated and stannylated enamides are obtained with excellent α,- or β,-selectivities and a broad functional group tolerance. Such a regiodivergent palladium-catalyzed process is unique in ynamide chemistry and allows for the elaboration of metalated enamides that are useful building blocks for cross-coupling reactions or heterocyclic chemistry. DFT calculations fully support the experimental data and demonstrate the crucial roles of the -geometry of the [H-Pd(L)-Ge] complex, as well as of the steric requirements of the phosphine ligand. In addition, these calculations support the prevalence of a hydro-palladation pathway over a metal palladation of the π system of the ynamide.
酰胺是一类引人入胜的小分子，在自由基、离子和金属催化条件下具有互补的反应性。我们在此报告了钯催化的酰胺配体控制的区域选择性水合金属化反应的合成和 DFT 研究。通过该方法，可获得具有优异的 α-或 β-选择性和广泛的官能团容忍度的锗基和锡基烯酰胺。这种区域选择性的钯催化过程在酰胺化学中是独特的，它可以制备出金属化的烯酰胺，这些烯酰胺是用于交叉偶联反应或杂环化学的有用构建块。DFT 计算完全支持实验数据，并证明了 [H-Pd(L)-Ge] 配合物的 - 几何形状以及膦配体的空间位阻的关键作用。此外，这些计算还支持了氢钯化途径相对于酰胺的π 体系的金属钯化的普遍性。
