Regio-Selective Phosphation and Phosphonation of 9-Fluorenones

A method for regio-selective phosphation and phopshonation at 9-position of fluorenones has been developed. The outcome of reaction can be controlled by varying temperature viz., at low temperature phosphonate is the exclusive product, whereas at high temperature phosphate is the favoured product. The reaction is easy to set up, involves mild conditions and proceeds efficiently over a broad range of substrates with excellent functional group tolerance.