Reversal of Diastereoselectivity of Mesitonitrile Oxide 1,3-Dipolar Cycloadditions with Penta-1,4-diene-3-ol by Mg(II)

摘要

1,3-Dipolar cycloadditions of mesitonitrile oxide (4) to penta-1,4-diene-3-ol (5) proceed regioselectively irrespective of the presence or absence of the Mg(II) additive Addition of Grignard reagent reverses the diastereoselectivity of the cycloaddition.The reaction of mesitonitrile oxide with magnesium alkoxide of penta-1,4-diene-3-ol (5) proceeded with exclusive diastereoselectivity giving the syn 6b and 7c isomer of the resulting isoxazolines.