Effect of lithium complexation by 12-crown-4 on the regioselectivity of the attack of GEM-dichloroallyl-lithium on some carbonyl compounds

✍ Scribed by Enrico Angeletti; Roberto Baima; Carlo Canepa; Iacopo Degani; Glauco Tonachini; Paolo Venturello

• Publisher: Elsevier Science
• Year: 1989
• Tongue: French
• Weight: 410 KB
• Volume: 45
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)85797-5

✦ Synopsis

Substituted benzaldehydes and acetoph.enone preferentially attack the y position of gem-dichloro ally1 anion, but show a significantly increased a-selectivity if 12-crown-4 is present. This behaviour is discussed on the basis of theoretical computations. 3,3-Dichloropropene and 12-crown-4 were stored over molecular sieves. 1H NMR spectra were recorded on a Hitachi Perkin-Elmer R-24B 60 MHz high