Enantioselective Synthesis of Spirocyclic Aminochroman Derivatives According to the CN(R,S) Strategy

Enantiomerically pure (3‘R)- and (3‘S)-3‘,4‘-dihydrospiro[piperidine-2,3‘(2‘H)-benzopyran]s (R)-10 and (S)-10 were successfully synthesized according to the CN(R,S) methodology with the aim of serving as a pattern for the generation of related spirocyclic compounds. Two different synthetic pathways were studied starting from 2-cyano-6-phenyloxazolopiperidine (−)-2. One of them was selected and used for the preparation of amines (R)-17 and (S)-17 starting from (−)-2 and (+)-2, respectively. The enantiomeric purity of all final aminochroman derivatives was determinated by capillary electrophoresis using β-cyclodextrin as the chiral selector.