To What extent is a π-allylic intermediate involved in some palladium-catalyzed alkylations ?
作者:J.C. Fiaud、J.L. Malleron
DOI:10.1016/s0040-4039(01)90332-6
日期:1981.1
Comparison of polarimetric data in the asymmetric palladium-catalyzed addition of sodium dimethyl malonate on optically active and racemic 2-cyclohexenyl and carveyl acetates suggests that the reaction does not got - at least totally - through a symmetric π-allylic cationic intermediate.
A convenient procedure for smooth palladium-catalyzed allylic alkylation by sodium dimethyl malonate and cyclopentadienide. A new synthesis of allylic substituted cyclopentadienes.
作者:J.C. Fiaud、J.L. Malleron
DOI:10.1016/s0040-4039(00)92193-2
日期:——
The use of the Pd(dba)12/dpe catalytic system in allylic alkylation allows sodium dimethyl malonate to react with allylicacetates at room temperature. According to this procedure, a novel synthesis of allylicsubstituted cyclopentadienes is described through the use of cyclopentadienide anion as a nucleophile.
N-Heterocyclic carbenes as ligands in palladium-catalyzed Tsuji–Trost allylic substitution
作者:Yoshihiro Sato、Taro Yoshino、Miwako Mori
DOI:10.1016/j.jorganchem.2005.07.043
日期:2005.12
reaction. Allylicsubstitutionusing a Pd–NHC complex differed from that using a Pd–phosphine complex as follows: (1) the reaction using a Pd–NHC complex required elevated temperature (50 °C or reflux in THF), (2) allylic carbonates were inert to a Pd–NHC complex, and (3) nitrogen nucleophiles such as sulfonamide and amine did not react with allylic acetate. It was also found that allylicsubstitution with
研究了使用N-杂环卡宾作为配体的Pd(0)催化的烯丙基取代(即Tsuji-Trost反应)。业已证明,在咪唑-2-亚烷基骨架中的氮原子上带有庞大的芳香环的咪唑鎓盐2d适合用作配体前体,并且Pd 2 dba 3-咪唑鎓盐2d -Cs 2 CO 3该系统对于在该反应中生产Pd-NHC催化剂非常有效。使用Pd-NHC络合物的烯丙基取代与使用Pd-膦络合物的烯丙基取代具有以下区别:(1)使用Pd-NHC络合物的反应需要升高的温度(50°C或在THF中回流),(2)烯丙基碳酸酯对Pd-NHC络合物呈惰性,并且(3)氮亲核试剂(如磺酰胺和胺)不会与乙酸烯丙酯反应。还发现使用Pd-NHC催化剂用软亲核试剂进行烯丙基取代是通过整体保留构型而进行的,从而以立体特异性方式得到产物,立体化学反应过程显然与使用Pd-膦的反应相同。复杂的。