Heterocyclic Merging of Stereochemically Diverse Chiral Piperazines and Morpholines with Indazoles

Abstract

AbstractWe report a heterocyclic merging approach to construct novel indazolo‐piperazines and indazolo‐morpholines. Starting from chiral diamines and amino alcohols, novel regiochemically (1,3 and 1,4) and stereochemically diverse (relative and absolute) cohorts of indazolo‐piperazines and indazolo‐morpholines were obtained within six or seven steps. The key transformations involved are a Smiles rearrangement to generate the indazole core structure and a late‐stage Michael addition to build the piperazine and morpholine heterocycles. We further explored additional vector diversity by incorporating substitutions on the indazole aromatic ring, generating a total of 20 unique, enantiomerically pure heterocyclic scaffolds.