Copper‐Mediated Dichotomic Borylation of Alkyne Carbonates: Stereoselective Access to (
<i>E</i>
)‐1,2‐Diborylated 1,3‐Dienes versus Traceless Monoborylation Affording α‐Hydroxyallenes
作者:Kun Guo、Arjan W. Kleij
DOI:10.1002/anie.202014310
日期:2021.2.23
A mild copper‐mediated protocol has been developed for borylation of alkynyl cyclic carbonates. Depending on the nature of the borylating reaction partner, either stereoselective diborylation of the propargylic surrogate takes place, providing convenient access to (E)‐1,2‐borylated 1,3‐dienes, or traceless monoborylation occurs, which leads to α‐hydroxyallenes as the principal product. The dichotomy
已经开发了一种温和的铜介导方案,用于炔基环状碳酸酯的硼酸酯化。取决于硼化反应伙伴的性质,发生炔丙基替代物的立体选择性二硼基化,提供与(E)-1,2-硼基化的1,3-二烯的便捷连接,或者发生无痕的单硼化,从而导致α-羟基丙二烯作为主要产品。该硼化方案的二分法已通过多个对照实验进行了详细研究,表明diboron(4)试剂的相对较小变化允许在环境条件下竞争性的醇辅助原金属脱除而伪造出α-羟基丙二烯产物。