Diels-Alder cycloaddition between the fumarate of methyl (S)-mandelate (22) and alpha-hydroxy-alpha-aryl-o-quinodimethane 21 produces an endo cycloadduct (23) in 58% yield. The preparation of the precursor to o-quinodimethane 21 and the conversion of cycloadduct 23 to optically pure (-)-deoxypodophyllotoxin (1) is described.