Efficient solvent free synthesis of tertiary α-aminophosphonates using H2Ti3O7 nanotubes as a reusable solid-acid catalyst

In this paper, TiO2 fine particles, TiO2-P25, protonated trititanate (H2Ti3O7) nanorods and nanotubes were used as recyclable solid-acid catalysts for the solvent free synthesis of tertiary CL-aminophosphonates through Kabachnik Fields reaction. Among them, H2Ti3O7 nanotubes showed remarkable catalytic performance and it was due to strong and sufficient Lewis and Bronsted acid sites on a large nanotubular surface. More importantly, for the first time we reported some novel 5,8-dioxa-10-azadispiro[2.0.4.3]undecane bearing tertiary CL-aminophosphonates.