ACTIVATED ALKYL-ALKALI AND ALLYL-ALKALI METAL REAGENTS - CONTRASTING BEHAVIOR TOWARDS ETHYLENE

Ethylene, hex-1-ene and (+)-alpha-pinene were readily metallated in me thylcyclohexane with the SySteM (n)BuLi/LiK(OCH2CH2N-Me2)2. The regios electivity of the reaction of metallated hex-1-ene and (+)-alpha-pinen e with CO2 could be substantially modified by the addition of Mg(OCH2C H2OEt)2. Addition of the latter also solubilizes the organometallic re agents. The allylmetallic products from the metallation of hex-1-ene a nd alpha-pinene added to ethylene under mild conditions. Whereas up to four molecules of ethylene added to metallated hex-1-ene, only one or two, depending on the reactant ratios, added to metallated alpha-pine ne. Similar reactions involving use of a variety of other strong bases such as (n)BuLi/1C5H11 OK and (n)BuM (M = Li, Na, K), with and withou t added TMEDA, indicated that the presence of a tertiary amine, apart from assisting the metallation reaction, is essential for the occurren ce of the addition.