Abstract Chiral tertiary dichloromethylcarbinol derivatives 2, prepared from protected chiral secondary alcohols 1, were converted stereospecifically into chiral quaternary α-oxygenated aldehyde derivatives 4 and 11 via intermediary α-chloroepoxides 3 under weakly basic conditions (K 2 CO 3/MeOH/rt). The fashion generating the quaternary centers was proved to be quite different depending on the substrates: inversion of configuration of non-benzylic ...