Coupling reaction of aryl iodides and benzocyclobutanol: A Computational Study

• 1、School of Chemistry and Chemical Engineering,Chongqing University, Chongqing 401331

Abstract：Density functional theory (DFT) calculations were employed to study palladium-catalyzed cross-coupling reaction of o-iodoaryl-derived allyl ethers and benzocyclobutanol.The mechanism of this reaction is consist of oxidative addition, alkene insertion, O-H Activation, β-C elimination and reductive elimination. Theoretical calculations indicate that, the regioselectivity is controlled by the alkene insertion step, the regioselectivity-limiting step and the rate-limiting step is the β-C elimination. Our computational results demonstrated that, R-configurational 2,3-dihydrobenzofuran skeleton is confirmed to be the major product. Independent gradient model analysis shows that spatial effects affect the stereoselectivity of olefin migration and insertion reactions. The R-configurational five-membered Pd(II) intermediate could afford through alkene insertion transition state, which reveals smaller steric interaction. In contrast, the S-configurational five-membered Pd(II) could be formed via palladacycle transition state with larger repulsion between alkene and tert-butyl, and between benzene and cyclohexyl. The geometric distortion of the benzocyclobutanol is the main reason for the regioselectivity of β-C elimination.

Keywords： olefin migration DFT alculation steric effects Pd catalysis