Muñiz Kilian, Streuff Jan, Chávez Patricia, Hövelmann Claas H
Institut de Chimie, UMR 7177, Université Louis Pasteur, France.
Chem Asian J. 2008 Sep 1;3(8-9):1248-55. doi: 10.1002/asia.200800148.
Unligated palladium(II) salts catalyze the oxidative diamination of acrylic esters to yield 2,3-diamino carboxylic esters. The reaction employs copper(II) bromide as oxidant and proceeds with good to excellent stereoselectivities and complete chemoselectivity. Preliminary mechanistic studies provide evidence for the involvement of a direct amination of the C--Pd bond in the alpha position relative to the ester group. This protocol significantly broadens the overall scope of the palladium-catalyzed diamination of alkenes and represents the first direct diamination of functionalized nonterminal substrates. The reaction yields readily protected 2,3-diamino acid derivatives, which can be considered as highly functionalized building blocks for subsequent synthesis. The use of one of these new diamination products as a suitable starting material in a short synthesis of the alkaloid absouline is demonstrated as an example.
未配位的钯（II）盐催化丙烯酸酯的氧化双胺化反应，生成2,3 - 二氨基羧酸酯。该反应使用溴化铜（II）作为氧化剂，具有良好到优异的立体选择性和完全的化学选择性。初步的机理研究表明，相对于酯基，α位的C - Pd键直接胺化参与了反应。该方法显著拓宽了钯催化烯烃双胺化反应的整体范围，代表了官能化非末端底物的首次直接双胺化反应。该反应容易得到受保护的2,3 - 二氨基酸衍生物，可被视为后续合成的高度官能化的构建单元。以其中一种新的双胺化产物作为合适的起始原料，在短时间内合成生物碱阿苏林为例进行了展示。
