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 α-aminophosphonates through Kabachnik–Fields reaction. Among them, H₂Ti₃O₇ nanotubes showed remarkable catalytic performance and it was due to strong and sufficient Lewis and Brønsted 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 α-aminophosphonates. [ABSTRACT FROM AUTHOR]