Synthesis of ( R)-Boc-2-methylproline via a Memory of Chirality Cyclization. Application to the Synthesis of Veliparib, a Poly(ADP-ribose) Polymerase Inhibitor.

( R)-Boc-2-methylproline (3a) was synthesized in good yield with excellent stereochemical control from alanine benzyl ester hydrochloride 11. The process, which is based on a modification of one described by Kawabata, proceeds in four steps and requires no chromatography. The product ( R)-Boc-2-methylproline (3a) was then carried forward in three steps to produce veliparib 1, a poly(ADP-ribose) polymerase inhibitor.

Discovery and Development of Metal-Catalyzed Coupling Reactions in the Synthesis of Dasabuvir, an HCV-Polymerase Inhibitor.

Dasabuvir (1) is an HCV polymerase inhibitor which has been developed as a part of a three-component direct-acting antiviral combination therapy. During the course of the development of the synthetic route, two novel coupling reactions were developed. First, the copper-catalyzed coupling of uracil with aryl iodides, employing picolinamide 16 as the ligand, was discovered.

A facile method for the preparation of MOM-protected carbamates.

A novel method for the preparation of MOM-protected carbamates is described that avoids the use of MOM-Cl, a regulated carcinogen. The two-step, one-pot procedure generates a reactive N-chloromethyl carbamate that is quenched with methanol to afford MOM-protected carbamates. The process is tolerant of a variety of functionalities, including Boc, sulfonamide, and acetamide protecting groups.