New methodology for the [4+3] cycloaddition reactions: generation of oxyallyl cations from α,α′-diiodoketones under sonochemical or thermal conditions

✍ Scribed by Angel M Montaña; Pedro M Grima

• Publisher: Elsevier Science
• Year: 2001
• Tongue: French
• Weight: 104 KB
• Volume: 42
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)01671-9

✦ Synopsis

A new methodology to perform [4+3] cycloaddition reactions of suitable dienes and 1,3-dimethyl-2-oxyallyl cations is presented. The reaction is carried out starting from commercially available dienes and easy-handling a,a%-diiodoketones, which are reduced by the Zn/Cu couple to generate the oxyallyl cation as intermediate. The reaction is carried out under mild thermal or sonochemical conditions at low temperatures (from 0 to -44°C) and for short reaction times (<15 min). This methodology represents a good alternative respect to the actual procedures based on other reducing agents or starting from more elaborate precursors of the oxyallyl cations.