Asymmetric alkylation of diphenylmethane derivatives using (−)-sparteine

Alkylation of 2-oxygenated diphenylmethane derivatives using sec-butyllithium and (−)-sparteine gave enantiomeric excesses of up to 60% with allyl bromide but alkylations with methyl electrophiles were poorly selective. When compounds with a free hydroxy in the 2-position were alkylated the selectivity was reversed.