Spiropiperidine Sultam and Lactam Templates: Diastereoselective Overman Rearrangement and Metathesis followed by NH Arylation.
Luis A Martinez-AlsinaJohn C MurrayLeanne M BuzonMark W BundesmannJoseph M YoungBrian T O'NeillPublished in: The Journal of organic chemistry (2017)
We report the diastereoselective synthesis of novel spiropiperidine templates for use in SAR studies of β-secretase (BACE) inhibitors and also as versatile ligands for other receptor types. The overall synthetic approach stems from chiral starting material benzyl (S)-2-methyl-4-oxopiperidine-1-carboxylate and employs an Overman rearrangement to control the stereochemistry at the quaternary center. This process is followed by a Grubbs metathesis to close a five-membered "top" ring to form an α,β-unsaturated lactam or an α,β-unsaturated sultam. We also demonstrate that this chemistry can accommodate additional substituents on the lactam/sultam ring and allows late stage sequential functionalization of the amine and amide nitrogens to rapidly produce diverse analogues.