Trisoxazolines

Trisoxazolines (Often abbreviated TRISOX or TOX) are a class of tridentate, chiral ligands composed of three oxazoline rings.

Despite being neutral they are able to form stable complexes with high oxidation state metals, such as rare earths,[1] due to the chelate effect.

Trisoxazolines can either be synthesised directly, from suitable tripodal starting materials, or built up in a modular manner.

In general synthesis involves the generation of separate mono‑oxazoline (typically halogenated) and bis-oxazoline units, which are then coupled using a strong base such as tBuLi[8] or KN(SiMe3)2.

[9] Trisoxazolines have been used for the copper catalysed Friedel–Crafts alkylation of indoles, largely with alkylidene malonates, with good yields and ee's reported.