Double Heck Route to a Dibenzoxepine and Convergent Suzuki Cross-Coupling Strategy for the Synthesis of an MR Antagonist

A practical pilot plant convergent synthesis of MR antagonist LY2623091 was established. For synthesis convergence, a vinyl bromide geometric isomer and chiral alaninol derivative were required building blocks. Key to the synthesis route development is a stereoselective synthesis of the E-vinyl bromide via a sequential double Heck reaction, Suzuki-Miyaura cross-coupling of the vinyl bromide, a selective nitro reduction, and a highly sensitive cyanamide hydrolysis to the urea. Improvements in yield and processing were accomplished by two sets of telescoping methods which decreased the manufacturing time and provided purity enhancements.