Mechanism and diastereoselectivity of the prebiotic synthesis of deoxyribonucleotide precursors C5-thiazoline: A DFT study

The prebiotic synthesis of deoxyribonucleotide precursor C5-thiazoline has been studied by performing density functional theory calculations. Two possible reaction pathways are explored and the results indicate that it prefers stepwise nucleophilic addition and ring-closure processes rather than concerted pathway. Four possible channels associated with four diastereoisomers have been explored in detail. Our calculations show that the C–C bond-forming step can be regarded as the rate-determining step and thiazole addition to the Si-face of iminium represents an energetically preferred pathway. In addition, the origin of diastereoselectivity is also investigated and the steric hindrance is considered to play a very important role. The current theoretical study provides very important information for in-depth understanding of other prebiotic nucleotides synthesis.