Introduction of Non-functional Alkyl and Reactive Allyl Groups

4 Introduction of Non-functional Alkyl and Reactive Allyl Groups 

The introduction of additional alkyl groups mostly involves the formation of a bond between a carbanion and a carbon attached to a suitable leaving group. S,.,2-reactions prevail, although radical mechanisms are also possible, especially if organometallic compounds are involved. Since many carbanions and radicals are easily oxidized by oxygen, working under inert gas is advised, until it has been shown for each specific reaction that air has no harmful effect on yields. 

The following aspects are important for alkylation reactions in the synthesis of complex molecules and will be exemplified  

The methods employed to solve such problems of regio- and stereoselectivity involve  

The simplest case is the substitution of a halogen at a saturated carbon atom by an alkyl group. Organocopper reagents exhibit strong carbanionic capacity, and do attack ester groups only slowly (D.E. Bergbreiter, 1975). Ketones, however, should be protected. The relative re- 

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