Construction Of Fused O-Hydroxybenzaldehyde From Tetraynes And Mechanism Research

o-Hydroxybenzaldehyde is an important intermediate in the production of perfumes, dyes, plastics, drugs, photosensitive material, agricultural and electroplating chemicals, such as Salinazid, Benzbromarone, and Aspirin. The ever-increasing demand for new fused o-hydroxybenzaldehyde, pharmaceuticals and agrochemicals in particular, continues to nurture tremendous interest in efficient and easy synthesis.The HDDA cyclization reactions of palladium-catalyzed tetraynes derivatives and N,N-dimethylformamide derivatives were studied. Through the optimization of the reaction conditions, we developed a mild catalyst-free synthesis of o-hydroxybenzaldehyde skeleton compounds in good to excellent yields. This method was simple, also accorded with the requirement of atom economy of green chemistry. N,N-dimethylformamide and water reacted directly with various substituents(p-F, p-CH3, p-CH2CH3, o-Cl) tetraynes derivatives. Tetraynes derivatives and N,N-dimethylformamide derivatives and water could effectively react at 115 ? produced 20 polycyclic compounds with o-hydroxybenzaldehyde skeleton structure. We proposed the possibly mechanism of the reaction, tetraynes substrates formed benzyne intermediates by self-cyclization then reacted with N,N-dimethylformamide and water to get the o-hydroxybenzaldehyde skeleton structure compounds through the HDDA reaction. All compounds were characterized by 1H NMR, 13 C NMR, IR, and HRMS, structures of two products were also confirmed by X- ray single crystal structure analysis.Furthermore, the cyclization reactions of palladium-catalyzed tetraynes derivatives and N,N- dimethylacetophenone derivatives were studied. We also developed a mild catalyst-free synthesis of o-hydroxyacetophenone skeleton compounds in good to excellent yields.