Enantioselective construction of alicyclic bicyclo[3.1.0]hexane framework by double stereodifferentiation and its application for the synthesis of both enantiomers of vitamin D3 CD ring synthons

✍ Scribed by Mingqi He; Shinji Tanimori; Susumu Ohira; Mitsuru Nakayama

• Book ID: 104208045
• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 449 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(97)00869-7

✦ Synopsis

A b s t rac t: Good diastereoselectivity (85:15) was observed in the intramolecular cyclopropanation of the chiral unsaturated ¢t-diazo-ffketo ester 9t, which possesses (R)-pantolactone as a chiral auxiliary. The reaction was catalyzed by a chiral bis-oxazoline copper (I) complex 17. The absolute stemochemistry of each generated diasl~reomer (10f and 1 If) was elucidated. Both enantiome~.~ of the vitamin D 3 CD ring synthons ((-)-2 1 and (+)-22) were synthesized from (-)-1 2 and (+)-13. respectively.