Three-Step Synthesis of 2-Acetyl-4-methyl-3,4-dihydropyran Oximes from Acetylbenzenes and Acetylene

2-Acetyl-4-methyl-3,4-dihydropyrans reacted with hydroxylamine in pyridine to give (E)-1-(4-methyl-3,4-dihydro-2H-pyran-2-yl)ethan-1-one oximes in up to 85% yield with high stereoselectivity.