Reaction of 1,2-bis(diorganophosphino)ethanenickel dibromide (I) with 1,2,3,4-tetraphenyl-1,4-dilithiumbutadiene (II) at −30°C yields diphosphannickelacyclopentadiene (III) which at elevated temperatures isomerizes to diphosphanecyclobutadienenickel(0) (IV). The thermodynamic and kinetic parameters of the rearrangement were determined. The structural and conformational analyses of III were carried
1,2-双(二有机膦基)乙烷二溴化镍(I)与1,2,3,4-四苯基-1,4-二锂丁二烯(II)在-30°C下反应生成二磷烷基镍环戊二烯(III),在高温下异构化为二膦环丁二烯镍(0)(IV)。确定了重排的热力学和动力学参数。III的结构和构象分析是通过13 C NMR,31 P NMR和拉曼光谱法进行的。III和IV与CH 3 COOH,CO,RCCR和RNCNR的反应已被氨化,并讨论了所观察到的反应性III IIIIV。
Photoinduced Electron-Transfer Bicyclopropenyl-benzene Rearrangements of 2,2‘,3,3‘-Tetraphenylbicyclopropenyls: A New Mechanism via Dewar Benzene
[reaction: see text] The 9,10-dicyanoanthracene-sensitized photoreaction of 1-methyl- and 1,1'-dimethyl-2,2',3,3'-tetraphenylbicyclopropenyl gives the corresponding benzene and Dewarbenzene derivatives, indicating that their photoinduced electron-transfer bicyclopropenyl-benzene rearrangements proceed via Dewarbenzenes.