Organocopper compounds reaction with epoxides

Sn2 Reactions with epoxides and aziridines are also synthetically useful. An example of epoxide cleavage with an organocopper reagent with sp carbon moieties is the enantioselective synthesis of (3S, 4S)-4-methyl-3-heptanol (53), an elm bark beetle (Scolytus multistriatus) pheromone [42]. The chiral epoxy oxazolidine 51 [43], prepared from (R)-phenylglycinol, reacted with a propylmagnesium bromide-derived cuprate at —70 °C to afford the oxazolidine 52 in 74% yield (Scheme 9.12). Compound 52 was converted into the target molecular 53 by conventional procedures. 

Hahdes of transition metals react with methyllithium to give methyl compounds. This reaction is alternatively afforded by organocopper compounds hke hthiumdialkylcuprates which are also known as Gilman reagents. These reagents are widely used for nucleophilic substitutions of epoxides, alkyl hahdes and for conjugate additions to a,p-unsaturated carbonyl compounds by methyl anion. 

---