A theoretical study on platinum-catalyzed cycloisomerization of 2-ethynyl-1-ferrocenylbenzene

Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): XingHui Zhang, LiPing Jiang, ShanShan Li, KeTai Wang Density functional theory calculations are carried out to explore the reaction mechanism for the cycloisomerization of 2-ethynyl-1-ferrocenylbenzene by using PtCl2 as a catalyst at the M06-2X/6-31G (d, p) (LanL2DZ (f) for Pt, Fe) level. The calculation results prove that the platinum-catalyzed cycloisomerization of 2-ethynyl-1-ferrocenylbenzene includes two possible pathways and three steps to afford naphthalene fused ferrocene. One reaction pathway is based on the 6-endo-dig cyclization mechanism, and another pathway is on the alkyne-vinylidene rearrangement mechanism. The channel 1 has a lower activation free energy by 17.0kcal/mol, which is more favorable to obtain the major product 2a. However, the activation barrier for the channel 2 is relatively high by 22.7kcal/mol. Through the detailed computational study, the results show that the platinum-catalyzed cycloisomerization has the good reactivity and high yield, giving a good explanation for the experimental observed major product. Graphical abstract

Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research