Development and Scale-Up of a Manufacturing Route for the Non-nucleoside Reverse Transcriptase Inhibitor GSK2248761A (IDX-899): Synthesis of an Advanced Key Chiral Intermediate

A new and improved synthetic route to an intermediate in the synthesis of the phosphinate ester GSK2248761A is described. In the key step, we describe the first process-scale example of a palladium-catalyzed phosphorus–carbon coupling to give the entire backbone of GSK2248761A in one telescoped stage in 65% average yield on a 68 kg scale. This unusual chemistry enabled the route to be reduced from six chemistry stages to four and eliminated a number of environmentally unfriendly reagents and solvents.