Straightforward Access to Chiral Phosphangulene Derivatives

Polycyclic aromatic hydrocarbons including heteroatoms have found a wide range of applications, for instance, in supramolecular chemistry or material science. Phosphangulene derivatives are P-containing polycyclic aromatic hydrocarbons presenting a concave aromatic surface suitable for building supramolecular receptors. However, the applications of this convenient building block have been strongly hampered by a difficult and multistep preparation requiring several protection-deprotection sequences along with the use of harmful reagents. Here, we report a straightforward, protecting-group-free, three-step, and hundred-milligram-scale synthesis of a chiral phosphangulene oxide derivative via a triple phospho-Fries rearrangement. This compound was easily resolved by chiral HPLC and further functionalized, giving rise to versatile chiral phosphangulene derivatives. Following this strategy, chiral phosphangulene oxides with low symmetry were synthesized. Molecular crystal structures revealed a variety of molecular organization in the solid. This opens the way to wider use of this compound as a building block for cages or new materials.