Abstract The cross-conjugated allenes (“allenic dendralenes”) 2-allenylbuta-1, 3-diene (2), 1, 1-divinylallene (3, prepared here as the methyl derivative 49), and 1, 1-diallenylethene (4) are prepared either by SN 2′-substitution processes from appropriate allenic or acetylenic precursors or by base-catalyzed isomerizations of propargylic substrates. Thermal elimination/isomerization routes to these highly unsaturated hydrocarbons require ...
