使用催化系统[(Pr i DAB)Pd(Me)(NCMe)] + [{{3,5-(CF 3)2 C 6 H 3 } 4 B] -,其中Pr i DAB = 1,4-二异丙基-1,4-二氮杂-1,3-丁二烯,有可能获得苯乙烯或p的共聚物-甲基苯乙烯与一氧化碳,具有交替的,从头到尾的间同结构,立体化学纯度为92%。为了研究反应机理,通过分离和表征反应中间体来研究共聚的第一步。研究了催化剂对一氧化碳的反应活性,并分离出相应的甲基羰基钯钯引发剂配合物。p的区域特异性2,1插入通过在第一个中间体五元的Palladacycle上进行的NOE测量证明了Pd-酰基键中的-甲基苯乙烯,其中乙酰氧与钯配位。此外,在质子和碳13 NMR光谱中,第二步插入CO和苯乙烯后产生的中间体出乎意料地显示出信号加倍。该发现归因于两种非对映异构体复合物的存在,表明在共聚的初始步骤中,链端立体化学控制并不完全有效。最后,研究了
Synthesis of a Novel α-Diimine Palladium(II) Complex Bearing an η<sup>3</sup>-Allyl γ-Lactone Ligand, a Key Intermediate in Alkyne Cyclocarbonylation Processes
Reactivity of [Pd(CH3)(CO)(PriDAB)]+[B3,5-(CF3)2C6H3}4]- (1), where PriDAB = 1,4-diisopropyl-1,4-diaza-1,3-butadiene, toward alkynes and carbon monoxide was investigated. While the reaction of 1 with phenylacetylene produced stereoregular homopolymer, a stoichiometric insertion of 1-phenyl-1-propyne and 2-butyne into the Pd−acyl bond yielded the palladacycles 2 and 3; subsequent reaction with CO resulted
[Pd(CH 3)(CO)(Pr i DAB)] + [B 3,5-(CF 3)2 C 6 H 3 } 4 ] -(1)的反应性,其中Pr i DAB = 1,4研究了-二异丙基-1,4-二氮杂-1,3-丁二烯对炔烃和一氧化碳的影响。尽管1与苯乙炔的反应生成了立体有规均聚物,但将化学计量的1-苯基-1-丙炔和2-丁炔插入Pd-酰基键后生成了pallaDAcycles 2和3;随后与CO反应导致形成新的络合物4和参见图5,其代表了炔烃环羰基化过程中关键中间体的第一个实验证据。
Quantitative formation of the intermediate of alkene insertion in the copolymerization of p-methylstyrene and carbon monoxide catalyzed by [(PriDAB)Pd(Me)(NCMe)]+BAr4−
作者:Carla Carfagna
DOI:10.1039/a801158c
日期:——
The intermediate after the first CO and p-methylstyrene insertion in the chain growth process of the copolymerization of these monomers has been quantitatively obtained from [(PriDAB)Pd(Me)(NCMe)]+[3,5-(CF3)2C6H3}4B]â in CHCl3 at 20 °C.
在 20°C 时,从 CHCl3 中的[(PriDAB)Pd(Me)(NCMe)]+[3,5-(CF3)2C6H3}4B]â 中定量获得了这些单体共聚过程中第一次插入 CO 和对甲基苯乙烯后的中间体。