Quantum Chemical Study of Mechanisms of Organic Reactions: XIII. Reaction of Propargyl Chloride with Dipotassium Ethane-1,2-bis(thiolate) in the System Hydrazine Hydrate–Potassium Hydroxide. Heterocyclization Pathways

The reaction of propargyl chloride with ethane-1,2-bis(thiolate) in the system hydrazine hydrate–potassium hydroxide has been simulated using the combined CCSD(T)/6-31+G*//B3LYP/6-311++G** approach. Elementary steps of the process and possible heterocyclization pathways of the primary intermediates have been identified. Under experimental conditions (40–42°C, 6 h), the title reaction produced 25% of 2-methyl-5,6-dihydro-1,4-dithiine and 24% of 4,7-dithiadeca-2,8-diyne. No cyclic products were formed at –10 to –15°C.