Synthesis of a CGRP Receptor Antagonist via an Asymmetric Synthesis of 3-Fluoro-4-aminopiperidine

J Org Chem. 2019 Jun 21;84(12):8006-8018. doi: 10.1021/acs.joc.9b00569. Epub 2019 Jun 5.

Abstract

A practical and efficient enantioselective synthesis of the calcitonin gene-related peptide receptor antagonist 1 has been developed. The key structural component of the active pharmaceutical ingredient is a syn-1,2-amino-fluoropiperidine 4. Two approaches were developed to synthesize this important pharmacophore. Initially, Ru-catalyzed asymmetric hydrogenation of fluoride-substituted enamide 8 enabled the synthesis of sufficient quantities of compound 1 to support early preclinical studies. Subsequently, a novel, cost-effective route to this intermediate was developed utilizing a dynamic kinetic asymmetric transamination of ketone 9. This synthesis also features a robust Ullmann coupling to install a bis-aryl ether using a soluble Cu(I) catalyst. Finally, an enzymatic desymmetrization of meso-diester 7 was exploited for the construction of the γ-lactam moiety in 1.

MeSH terms

  • Amides / chemistry
  • Calcitonin Gene-Related Peptide Receptor Antagonists / chemical synthesis*
  • Calcitonin Gene-Related Peptide Receptor Antagonists / chemistry*
  • Chemistry Techniques, Synthetic
  • Lactams / chemistry
  • Phenol / chemistry
  • Piperidines / chemical synthesis*
  • Piperidines / chemistry*
  • Receptors, Calcitonin Gene-Related Peptide / metabolism*

Substances

  • 4-aminopiperidine
  • Amides
  • Calcitonin Gene-Related Peptide Receptor Antagonists
  • Lactams
  • Piperidines
  • Receptors, Calcitonin Gene-Related Peptide
  • Phenol