The Determination Of The Molar Equation For The Reaction Between 1a And 3 Diketene

In our initial experiments, a 19% yield of 3,4-dicarbonyl substituted furan 3a was obtained when α,β-unsaturated carbonyl (1a) and 1,3 diketone (2b) were employed for the reaction (Table 1, entry 1) in a 1:2 molar ratio in the presence of 10mg of CuO-NPs in EtOH at room temperature without any oxidizing agent. When molar ratio of the reactants 1a and 2b were increased to 1:3, an improvement in the yield to 28% was observed (Table 1, entry 2) and molar ratio 1:5 gives the highest yield in the same reaction conditions 38% (Table 1, entry 3). The polar solvent such as DMF, DMSO, H2O, Xylene also gave the desired products but in low yield, while no reactions occurred in acetonitrile, toluene (Table 1, entries 4−9).When we employed a mixture of solvent EtOH:H2O (4:1) slight increase of yield 46% was obtained (Table 1, entry 10), increasing the mixture of solvent ratio to 2:1give the yield 51% (Table 1, entry 11) and solvent ratio 1:1 give the highest yield 60% (Table 1, entry 12).

Next, we turned our attention to the effect of oxidants. When various oxidants such as TBHP, K2S2O8, and DDQ were scrutinized (Table 1, entry 13-15), and TBHP (1 equiv) had the beneficial effect to give the best yield (Table 1, 75%; entry 13). However, the yield lowered when the amount of TBHP was decreased. The reaction did not proceed at all in the presence of other nano-particles, such as ZrO2, Fe3O4, NiO and in some copper salts CuBr2, CuCl2, (Table 1, entries