Deoxygenative phosphonation of ketones by titanium.

Tertiary phosphine oxides are ubiquitous motifs with essential roles across synthetic chemistry and life sciences, yet C(sp3)-P coupling remains underdeveloped. Herein, we report an accessible di-oxo-titanium trichloride complex, operating in combination with Mn powder, that enables a deoxygenative C(sp3)-P coupling of ketones with secondary phosphine oxides. The transformation proceeds under mild conditions and shows good compatibility with carbonyl substrates, including cyclic and acyclic ketones, as well as aliphatic aldehydes. Functionalities such as carboxyl, acetal, alkyne, sulfonate, phenol, and alcohol are well tolerated.