无过渡金属参与的醚、醛和酰胺C—H键自由基炔基化和烯丙基化反应

Transition-Metal Free Radical-Mediated C—H Bond Alkynylation and Allylation of Ethers,Aldehydes and Amides

醚、醛和酰胺类化合物广泛存在于天然产物和药物分子中,并作为常见廉价原料应用于合成化学中.通过自由基反应途径实现杂原子α位C—H键官能化为这些化合物的结构改造提供了高效策略.报道了一例通过二三氟醋酸碘苯(PIFA)在光照下直接攫氢产生碳自由基实现C—H键炔基化和烯丙基化反应的新策略.该方法操作简单,能够以中等到良好的产率实现醚、醛和酰胺C—H键的炔基化和烯丙基化反应.反应条件温和,不需要使用过渡金属催化剂,官能团兼容性广,适用于醚、醛和酰胺以及形式多样的炔基和烯丙基砜试剂.

Ethers,aldehydes,and amides are widely found in natural products and pharmaceutical molecules,and employed as inexpensive materials in synthetic chemistry.Radical-mediated heteroatomicα-C—H bond functionalization provides an efficient strategy for structural modification of ethers,aldehydes,and amides.New approaches of C—H alkynylation and allylation through phenyliodine bis(trifluoroacetate)(PIFA)induced hydrogen atom transfer(HAT)under visible-light irradiation are reported.The method is operationally simple,leading to the corresponding alkynylated and allylated products in moderate to good yields.The protocol features mild and transition-metal free conditions,broad functional group compatibility,and is adapted to a diversity of ethers,aldehydes,and amides as well as various alkynylating and allylating reagents.