4-methylene-2-oxazolidinones, prepared via the corresponding O-propargyl carbamates, underwent nitrile oxide cycloaddition with benzonitrile oxide to give 5-spiro isoxazoline adducts with complete regioselectivity. Steric hindrance by atropisomerism around the N-aryl bond induced facial selectivity in these cycloadditions.
通过相应的O-炔
丙基氨基甲酸酯制得的N-芳基4-亚甲基-2-
恶唑烷酮经
一氧化氮环加成氧化
苄腈 给5-spiro
异恶唑啉加合物具有完全的区域选择性。在这些环加成反应中,N-芳基键周围的阻转异构引起的立体位阻导致面部选择性。