Scheme 1. Reaction Scope of the Sigmatropic Amination of Allenols.^a.

^aUnless otherwise noted, reactions were conducted using 2.5 mol % OV(OSi(p-ClC₆H₄)₃)₃, 1 equiv of allenol and 1.4 equiv of dial-kyl azodicarboxylate in DCE (1.0 M) at rt. Product E/Z ratio >20/1 unless otherwise specified ^bReaction performed with 5 mol % catalyst. ^cReaction performed at the 2.0 mmol scale. ^dReaction performed at 45 °C. ^eReaction performed with 2.0 equiv of dialkyl azodicarboxylate. ^fSlow addition of the allenol over three hours. ^gReaction performed at 35 °C.