a combination of pivalic acid and para-toluenesulfonic acid proved successful in favoring the selective highly chemo- and regioselective tail-to-tail reductive dimerization of terminal alkynes over the competitive head-to-tail dimerization pathway. The target reaction, proposed to proceed via a cationic alkenyl palladium intermediate, presents a facile and straightforward approach for accessing 2,3-dibranched
使用
新戊酸和
对甲苯磺酸的组合证明成功地有利于末端
炔烃的选择性高度
化学和区域选择性的尾对尾还原二聚化,而不是竞争性的头对尾二聚化途径。建议通过阳离子链
烯基
钯中间体进行的目标反应为获得 2,3-二支化
丁二烯提供了一种简便直接的方法。