Stereoselective Preparation of Allylmetallic Reagents

Such a sequence has been successfully used115 for the synthesis of 4-methyl-3-heptanol, the major constituent of the aggregation pheromone of the elm bark beetle (Scolytus multistriatus Marsham)117 and zir-butyM-methyltetrahydro-2-furanone118 known as quercus lactone or oak lactone.  

Dialkylallyl boranes have also been prepared119 by metallation of alkenes with trimethylsilylmethylpotassium followed by trapping of the allylpotassium species with dialkylchloroboranes. Such allylboranes have been then used 

Stereochemically pure allylsilanes and stannanes can also be obtained by metallation of suitable olefins with the superbasic mixture of butyllithium and potassium /fV/-butoxide followed by reaction with trimethylchlorosilane and tributylchlorostannane, respectively. In a representative example, 6-(2-tetrahydropyra-nyloxy)hex-l-ene is transformed into Z-(6-hydroxyhex-2-enyl)trimethylsilane through metallation with trimethyl- 

---