Use of alkyl 2,4,6-triisopropylbenzoates in the asymmetric homologation of challenging boronic esters.

(-)-Sparteine induced lithiation of primary 2,4,6-triisopropylbenzoates and subsequent homologation of boronic esters is reported. A comparative study with lithiated N,N-diisopropylcarbamates has demonstrated the superiority of the hindered benzoate.