HFIP-Promoted Bis-Phosphorylation via Dual C-P Coupling of Unprotected sec-Propargylic Alcohols and Phosphites: Access to Substituted (Prop-2-ene-1,2-diyl)(E)-Bisphosphonates.

A first HFIP-promoted, direct coupling of unprotected secondary propargyl alcohols and phosphites has been developed, providing efficient access to substituted (prop-2-ene-1,2-diyl)(E)-bisphosphonates through the concurrent formation of P-C(sp2) and P-C(sp3) bonds. This transition-metal-free reaction proceeds rapidly at room temperature, featuring operational simplicity and scalability to gram quantities. Moreover, HFIP was recycled for further use by distillation, which makes this protocol a greener and more sustainable choice.