Synthesis of 2-pyranylidene or (2-furyl)carbene–chromium complexes from conjugated enyne carbonyl compounds with Cr(CO)5(THF)
作者:Koji Miki、Tomomi Yokoi、Fumiaki Nishino、Kouichi Ohe、Sakae Uemura
DOI:10.1016/s0022-328x(01)01328-6
日期:2002.2
β-unsaturated esters or amides with Cr(CO)5(L) (L=Et2O, THF), derived from chromium hexacarbonyl, gives 2-pyranylidene–chromium complexes in good yields. The conjugated ene-carbonyl-vinylidene complex is a key intermediate to these Fischer-type oxacarbene complexes. In contrast, β-ethynyl α,β-unsaturated ketones react with Cr(CO)5(THF) to give (2-furyl)carbene complexes via nucleophilic attack of the carbonyl
β-乙炔基α,β-不饱和酯或酰胺与六羰基铬衍生的Cr(CO)5(L)(L = Et 2 O,THF)的反应可得到高产率的2-吡喃基-铬络合物。共轭烯-羰基-亚乙烯基配合物是这些费歇尔型氧杂卡宾配合物的关键中间体。相反,β-乙炔基α,β-不饱和酮与Cr(CO)5(THF)反应,通过羰基氧原子对中间π-炔烃-铬络合物的亲核攻击生成(2-呋喃基)卡宾络合物。还描述了一些化学转化,例如2-炔基配合物与炔烃的[4 + 2]型环化以及由(2-呋喃基)卡宾配合物形成的醛。