Reactions or orthoformates with alkyllithium reagents. A novel synthesis of internal olefins.

✍ Scribed by K.Darrell Berlin; Brijraj S. Rathore

• Book ID: 104212107
• Publisher: Elsevier Science
• Year: 1964
• Tongue: French
• Weight: 200 KB
• Volume: 5
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)70384-4

✦ Synopsis

Orthoesters are converted to acetals nhen treated with GrignaM reagents (1.2). Surprisingly very Little work has been reported on reactions with lithium reagents. We have found that alkyllithium reagents react with several ort&esters to give internal olefins. For example, addition of I to butyllithium (1:5 molar ratio) under nitrogen in ether-cyclohexane was exothermic. When the H-C(mH313 CH 25 I II the mixture was slowly heated to 60' (1 hr.), a pmcipitate formed. The mixture was stirred at reflux for an additional 0.5 hr. and allowed to cool to room temp erature. Decomposition was effected with ice water, and distSU.ation of the organic phase gave trans+nonene. Infrared analysis showed a strong bandat 9691x1~1 for the tram double bond (3). Oxidative wonolysis of the olefin snd methylation of the acidic products with diazonmthane, gave methyl n-butyrate and methyl n-valerate. &-8X&l-2,6,7-trloxabicyclo[2.2.2]octane (4) and n-butyl-Lithium under similar conditions gave a vastly inproved yield of tram-4-nonene as shown in TABLE . In addition to startingmaterial,which could be isolated from both eqeriments, several minor components were detected by gas chromatog-