Asymmetric synthesis of a chroman derivative (vitamin e precursor)

Chromanmethanol $\text{2}$, a chiral intermediate for the synthesis of α-tocopherol $\text{1}$, is prepared from α-hydroxy aldehyde $\text{5}$, which is obtained by an asymmetric synthesis in over 95% ee.     

C3 epimerization and selective C2C3 bond fission of alkyl chrysanthemate

Treatment of alkyl chrysanthemate with Lewis acid leads to C₃ epimerization, while protonic acid treatment gives rise to selective C₂C₃ bond cleavage. The latter method is successfully applied to the synthesis of optically active tetrahydrolavandulol.     

A stereoselective synthesis of β,γ-disubstituted allylic alcohols of z-configuration

Reaction of alkyllithiums $\text{1}$ with isoprene epoxide $\text{2}$ gives β,γ-disubstituted allylic alcohols $\text{3}$ of Z-configuration. The reaction of π-lithiotricyclene as alkyllithium gives α-santalol $\text{5}$, which is one of the main constituents in East Indian sandalwood oil.     

A practical convenient homogeneous palladium-phosphine catalysis for hydrocarbonylation of chlorobenzenes

Significant catalytic activity as well as high selectivity of benzoic acid has been found for hydrocarbonylation of chlorobenzene by using a catalyst system composed of PdCl₂(PCy₃)₂---K₂CO₃ aqueous solution-triethylamine (Cy: cyclohexyl).