A Computational Study of a Prebiotic Synthesis of α-Tocopherol, Vitamin-E and Tocols

Abstract

The prebiotic synthesis of α-tocopherol and the tocols is postulated as a copolymerization of the planetary gases propyne, ethyne and carbon monoxide on a magnesium ion metalloporphyrin complex where the ligands are bonded on the metal or nitrogen pyrrole sites as a two site catalyst. The order of addition of the monomers to form the chroman residue of α-tocopherol is 2 ethyne, propyne, carbon monoxide, 2 ethyne, carbon monoxide leading to bonding on the catalyst to give a chroman derivative. The phytyl side-chain is formed from the successive addition of propyne and ethyne monomers where the isoprenoid residues formed are subsequently hydrogenated. The separation of the catalyst is facilitated by hydrogen radicals to give α-tocopherol. The reactions have been shown to be feasible from the overall enthalpy changes in the ZKE approximation at the HF and MP2 /6-31G* level, and with acceptable activation energies.