An efficient oximation method has been developed on the basis of NO + -initiated semipinacol rearrangement and subsequent proton elimination. The procedure enabled the rapid construction of aseries of oximes and oxime ethers with spiro quaternary stereocenters from allylic silyl ethers.A dditional features of this reaction include wide substrate tolerance as well as the commercial availability of the safe nitrosation reagent NOBF 4 .T he key N-heterotricyclic cores of three natural alkaloids,tuberostemoninol B, (+ +)-quebrachidine,and an insecticide,were also constructed efficiently by this method.