The new route to dehydrodeoxypodophyllotoxin cyclic ether (10) has been realized via allene intramolecular Diels-Alder reaction of the propargyl ether (8).
KANEMATSU, KEN;TSURUOKA, MICHIKO;TAKAOKA, YUMIKO;SASAKI, TAKUMA, HETEROCYCLES, 32,(1991) N, C. 859-862