Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (10): 1864-1871.doi: 10.3866/PKU.WHXB201508281

• THEORETICALAND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Reaction Mechanism and the Regioselectivity of Cu-Catalyzed Silacarboxylation of Internal Alkynes: a Density Functional Theory Study

Yi. ZHAO*(),Jin. ZHOU,Hui. LIU,Shu-Ping. ZHUO   

  • Received:2015-07-01 Published:2015-10-10
  • Contact: Yi. ZHAO E-mail:zhaoyichem@sina.com
  • Supported by:
    the National Natural Science Foundation of China(51302156, 21302057);Combined with Shandong ProvincialNatural Science Foundation, China(ZR2014BL012)

Abstract:

Transition metal-catalyzed carbon-carbon bond formation utilizing CO2 is of great importance. The heteroatom functionality and CO2 are simultaneously and catalytically incorporated into unsaturated substrates to form highly functionalized carboxylic acid derivatives. Here, density functional theory (DFT) is used to study the reaction mechanisms of the Cu-catalyzed silacarboxylation of internal alkynes. Two possible paths were proposed depending on the relative positions of the substituents (path I: methyl and path II: phenyl). The calculations reveal that the initial alkyne insertion into the Cu―Si bond determined both the rate and the selectivity. In path I, the calculated free energy barrier for alkyne insertion is 112.8 kJ·mol-1, while that in path II is 127.6 kJ·mol-1. Thus, path I is more kinetically favorable than path II, which is consistent with the experimentally observed product ratio of 97 : 3. Our analysis revealed that the electronic effects of the alkyne substituents dominated the observed regioselectivity.

Key words: Regioselectivity, Alkyne, Silacarboxylation, Carbon dioxide, Density functional theory

MSC2000: 

  • O643