Regioselectivity of 1,3-Dipolar Cycloadditions of Benzonitrile Oxide to Alkenyl Boronic Esters: An Experimental and Computational Study
作者:Jo Jeong、Kyukwan Zong、Joong Chul Choe
DOI:10.1002/jhet.2667
日期:2017.3
1,3‐Dipolar cycloaddition reactions of benzonitrile oxide to monosubstituted or 1,1‐disubstituted alkenyl boronic ester gave only 2‐isoxazolines, bearing the boronic ester group at the 5‐position of the ring. On the other hand, the cycloaddition reactions of benzonitrile oxide with trans‐1,2‐disubstituted alkenyl boronic esters produced 2‐isoxazolines, bearing the boronic ester group at the 4‐position
氧化苄腈与单取代或1,1-二取代的烯基硼酸酯的1,3-偶极环加成反应仅生成2-异恶唑啉,在环的5位带有硼酸酯基。另一方面,苯甲腈氧化物与反式1,2-二取代的烯基硼酸酯的环加成反应生成2-异恶唑啉,在环的4-位带有硼酸酯基团。我们使用量子力学计算研究了与2异恶唑啉的形成有关的两个区域异构通道,这些通道在4位或5位带有硼酸酯基。研究表明,实验结果与基于气相或溶剂相过渡态能量的参数非常吻合。