Epimerization and kinetic resolution in copper-catalyzed enantioselective 1,4-additions of organozinc reagents to 6-substituted cyclohex-2-enones

✍ Scribed by Laura Mediavilla Urbaneja; Alexandre Alexakis; Norbert Krause

• Book ID: 104252130
• Publisher: Elsevier Science
• Year: 2002
• Tongue: French
• Weight: 183 KB
• Volume: 43
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(02)01898-1

✦ Synopsis

Enantioselective 1,4-addition reactions of diethyl-, dimethyl-, and di-n-butylzinc to 6-methylcyclohex-2-enone (1) and 6-t-butylcyclohex-2-enone (4), catalyzed by Cu(OTf) 2 and phosphoramidites L1-L4 were examined. The additions to enone 1 proceeded with high enantioselectivity; by acid-or base-catalyzed epimerization, adduct (S,S)-2 can be obtained from racemic 1 in diastereo-and enantiomerically pure form. In contrast, Michael additions to substrate 4 were rather slow and could be used for the kinetic resolution of the enone.