High linear regioselectivity in the rhodium-catalyzed hydro(deuterio)formylation of 3,4,4-trimethylpent-1-ene: The role of β-hydride elimination
作者:Raffaello Lazzaroni、Roberta Settambolo、Giuliano Alagona、Caterina Ghio
DOI:10.1016/j.molcata.2011.12.021
日期:2012.4
reaction steps along branched and linear pathways have been examined to elucidate the origin of reaction reversibility. The TS for the alkyl migratory insertion onto the CO coordinated to rhodium, higher than that for the alkyl-Rh intermediate formation, explains the reason why in deuterioformylation experiments at partial conversion the monodeuterated terminal olefin TMP1-1-d1 is obtained. This occurs
在由未改性的Rh催化剂催化加氢甲酰化反应中的区域选择性已经研究了许多α-甲基替代烷-1-烯烃(3-甲基丁-1-烯MB 1,3-甲基戊-1-烯MP 1,3,(在20°C和100 atm CO / H 2的条件下)实验获得4-二甲基戊-1-烯DMP 1和3,4,4-三甲基戊-1-烯TMP 1)总压力),理论上为B3P86 / 6-31G *水平,Rh由LanL2DZ价基集中的有效核心电势描述。对于所有的底物,已经观察到相对于支化的一种(B)占主导地位的线性醛(L)的形成(L / B> 62/38);在TMP 1(L / B = 95/5)的情况下,L异构体几乎是排他的产物。来自部分底物转化中断的类似氘代甲酰化实验的粗反应混合物的2 H NMR研究表明,在TMP 1的情况下仅通过支链β-氢化物消除的支链醛的前体支链烷基铑中间体主要生成末端氘代烯烃,并在较小程度上生成内部烯烃。支链烷基-Rh中间体