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