A theoretical study on the mechanism of the addition reaction between carbene and epoxyethane

Abstract

The mechanism of addition reaction between carbene and epoxyethane has been investigated employing the MP2 and B3LYP/6-311?G* levels of theory. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the potential energy surface have been calculated. Based on the calculated results at the MP2/6-311?G* level of theory, it can be predicted that there are two reaction mechanisms (1) and (2). In the first reaction carbene attacks the atom O of epoxyethane to form an intermediate 1a (IM1a), which is a barrier-free exothermic reaction. Then, IM1a can isomerize to IM1b via a transition state 1a (TS1a), where the potential barrier is 48.6 kJ/mol. Subsequently, IM1b isomerizes to a product epoxypropane (Pro1) via TS1b with a potential barrier of 14.2 kJ/mol. In the second carbene attacks the atom C of epoxyethane firstly to form IM2 via TS2a. Then IM2 isomerizes to a product allyl alcohol (Pro2) via TS2b with a potential barrier of 101.6 kJ/mol. Correspondingly, the reaction energies for the reactions (1) and (2) are -448.4 and -501.6 kJ/mol, respectively. Additionally, the orbital interactions are also discussed for the leading intermediate. The results based on the B3LYP/6-311?G* level of theory are paralleled to those on the MP2/6-311?G* level of theory. Furthermore, the halogen and methyl substituent effects of H 2 C: on the two reaction mechanisms have been investigated. The calculated results indicate that the introductions of halogen or methyl make the addition reaction difficult to proceed.

Amino Acid-Assisted Dehalogenation of Carbon Tetrachloride by Green Rust: Inhibition of Chloroform Production

“…Contrary to the amine and good buffers, glycine (GLY) and other amino acids are capable of complexing a variety of metal ions, including Fe II ions. − It is likely that GLY also may affect dehalogenation due to its Fe II complexing ability. Furthermore, GLY as other amino acids can interact with carbene intermediates through the CO bond via an addition reaction. − According to Tan’s research, carbenes can attack GLY from the H 1 C 1 C 2 side (the numbering refer to the atom position in the molecule), and form an intermediate by coupling with the CO double bond, which is an exothermic reaction with a low energy barrier. Subsequently, the intermediate isomerizes to form the final products.…”

A Theoretical Study on the Mechanism of the Addition Reaction Between Cyclopropenylidene and Ethylene

“…Apeloig et al extensively studied the mechanisms and stereoselectivity of carbene addition to olefin experimentally and theoretically [9][10] . Recently, the reactions between carbene and small-ring strained molecules, such as epoxyethane and azacyclopropane, have been investigated theoretically [11][12] .…”

Insights into the reaction mechanism between propadienylidene and ethylene: a DFT study

“…Apeloig et al [9,10] extensively studied the mechanisms and stereoselectivity of carbene addition to olefin experimentally and theoretically. Recently, the reactions between carbene and small-ring strained molecules, such as epoxyethane and azacyclopropane, have been investigated by us [11,12].…”