Asymmetric spirocyclization: A new type of acid-catalyzed intramolecular 1, 4-addition to form carba-spirocyclic compounds

✍ Scribed by Satoshi Yamada; Satoru Karasawa; Youichi Takahashi; Mariko Aso; Hiroshi Suemune

• Book ID: 104208991
• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 763 KB
• Volume: 54
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(98)01009-6

✦ Synopsis

Novel spiroeyclization based on intramoleeular 1,4-eddition and its asymmetric version have been &vdoped using a combination of Lewis acid and 1,2-dioh Treatment of five-and six-mernbered ct,~unsaturated cyclic ketones having a 4-oxopentyl group at the ~position with Lewis acid and ethylene glycol gave spiro[4.5]deeane-2,7-~one and spiro[5.5]undecane-2,8-~one, respectively. The asymmetric version of this reaction has been developed by using optically active 1,2-diol such as cyclohexane-l,2-diol to afford the spirocyclie products of up to 85% e.e.