Cascade reactions with chiral michael acceptors; synthesis of enantiomerically pure tricyclo[3.2.1.02,7]- and bicyclo[3.2.1]octanes

✍ Scribed by Braun, Norbert A. ;Klein, Iris ;Spitzner, Dietrich ;Vogler, Bernhard ;Braun, Siegmar ;Borrmann, Horst ;Simon, Arndt

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 602 KB
• Volume: 1995
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.1995199512302

✦ Synopsis

Abstract

Starting from the easily accesible chiral aldehyde 2, we obtained enantiomerically pure (Z)‐ and (E)‐α,‐chloro‐α,β‐unsaturated esters 4c in good yields by olefination reactions. (Z)‐and (E)‐4c were allowed to react with the kinetically controlled generated lithium dienolate Li‐7 to give the enantiomerically pure tricyclo[3.2.1.0^2,7^]octanes 8 and 9, respectively. The „push‐pull”︁ substituted cyclopropane moiety of 8 was opened to give solely bicyclo[3.2.1]octane 10.