A mild and selective synthesis of cyclopropene and cyclopropane derivatives via cycliallylation of alkenyllithiums

✍ Scribed by A.Timothy Stoll; Ei-ichi Negishi

• Book ID: 104233357
• Publisher: Elsevier Science
• Year: 1985
• Tongue: French
• Weight: 297 KB
• Volume: 26
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)80915-1

✦ Synopsis

Treatment of cis-1-iodo-3-chloro-1-propene derivatives, readily obtainable via trans addition of organometals to propargyl alcohols followed by iodinolysis and chlorination, with alkyllithiums, such as t-BuLi and n-BuLi, can proceed rapidly and cleanly even at -78°C to give in high yields cyclopropene derivatives, which undergo cis hydrometalation and carbometalation reactions more rapidly than the corresponding alkynes to produce cyclopropane derivatives. Cyclopropenes are of interest from both theoretical and synthetic viewpoints. The heat of hydrogenation for the conversion of cyclopropene to cyclopropane is ca. 54 kcal/mole' and is considerably larger than that for the conversion of acetylene to ethylene (42 kcal/mole2), suggesting that cyclopropenes should be more reactive than the corresponding alkynes in hydrometalation, carbometalation, and other addition reactions. And yet, relatively little has been