Asymmetric induction using chiral 1,2,4-triazole and benzimidazole derivatives

✍ Scribed by Alan R. Katritzky; Diana C. Aslan; Peter Leeming; Peter J. Steel

• Book ID: 104361177
• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 627 KB
• Volume: 8
• Category: Article
• ISSN: 0957-4166
• DOI: 10.1016/s0957-4166(97)00155-9

✦ Synopsis

Lithiated N-substituted 1,2,4-triazoles 3 and 8 and benzimidazole 11 reacted with (1R)-fenchone to give derivatives 5c, 9 and 12 in good yields as single diastereoisomers. (S)-Lactic acid 16 reacted with o-phenylenediamine 15 to give optically pure (53-2-(1-hydroxyethyl)benzimidazole 17 (85%). Ring closures converted the fenchone derivative 12 into novel tricyclic fused benzimidazoles 13 and 14, and converted oxazolidine derivative 17 into compound 18 in yields of 50-70% as single diastereoisomers. Lithiated derivative 18 was alkylated to give compound 19 as a single diastereoisomer in high yield.