Dihydropyridines in Organometallic Synthesis. Formation of Pyridine and Dihydropyridine-Stabilized Alkylidene Complexes of Tungsten(0) and Chromium(0) from Fischer Carbene Complexes: Structure and Reactivity
作者:Henri Rudler、Max Audouin、Andrée Parlier、Blanca Martin-Vaca、Régis Goumont、Thomas Durand-Réville、Jacqueline Vaissermann
DOI:10.1021/ja9622057
日期:1996.1.1
1,2- and 1,4-dihydropyridines react with alkoxycarbene complexes of chromium and tungsten to give, upon an unprecedented hydride transfer, alcohol elimination, and pyridine fixation on the carbene carbon, a new class of air-stable pyridinium ylide complexes. These pyridine-protected alkylidene complexes of chromium(0) and tungsten(0) were fully characterized by X-ray crystallography. In the case of
1,2- 和 1,4- 二氢吡啶与铬和钨的烷氧基卡宾配合物反应,通过前所未有的氢化物转移、醇消除和吡啶固定在卡宾碳上,产生一类新的空气稳定的吡啶鎓叶立德配合物。这些吡啶保护的铬 (0) 和钨 (0) 亚烷基配合物通过 X 射线晶体学进行了充分表征。在 (CO)5WC(CH3)(OEt) (5a) 的情况下,除了吡啶鎓叶立德配合物 (CO)5W-−C(H)(CH3)(吡啶)+ (7a) 外,二氢吡啶鎓配合物 (CO) 5W--C(H)(CH3)(2,5-二氢吡啶)+(8a)也被分离。中间体钨酸盐 (CO)5W--C(H)(CH3)(OEt)(CH3NC5H5)+ 可以通过使用 N-甲基二氢吡啶作为还原剂很容易地获得和表征。而苯基取代的吡啶鎓配合物很容易将亚苄基部分转移到烯烃上,烷基取代的配合物似乎更不愿意进行这种转移:在亲核烯烃如烯醇醚的情况下观察到令人满意的结果。如何...