Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

Abstract

A terminal alkyne is one of the most useful reactants for the synthesis of alkyne and alkene derivatives. Because an alkyne undergoes addition reaction at a C–C triple bond or cross-coupling at a terminal C–H bond. Combining those reaction patterns could realize a new reaction methodology to synthesize complex molecules including C–C multiple bonds. In this report, we found that the reaction of 3 equivalents of terminal alkyne 1 (aryl substituted alkyne) and an α-bromocarbonyl compound 2 (tertiary alkyl radical precursor) undergoes tandem alkyl radical addition/Sonogashira coupling to produce 1,3-enyne compound 3 possessing a quaternary carbon in the presence of a copper catalyst. Moreover, the reaction of α-bromocarbonyl compound 2 and an alkyne 4 possessing a carboxamide moiety undergoes tandem alkyl radical addition/C–H coupling to produce indolinone derivative 5.

Mesoporous silica gel doped with dysprosium and modified with copper: A selective catalyst for the hydrogenation of 1‐hexyne/1‐hexene mixture

“…Copper-catalyzed reactions of alkynes have advanced significantly over the past few decades, and several useful reviews have been published on the chemistry of alkynes with copper metal. [33][34][35][36][37][38][39] In recent years, studies have been carried out on catalysts based on mesoporous materials doped with rare earth elements (REEs). In studies devoted to the influence of the promoting activity of various nature metals, in particular, when comparing the activity of REEs and d-elements, it was found that the catalyst doped with REE had the best performance.…”

“…The reason for the preferred use of copper lies in its low cost, non‐toxicity, and easy availability. Copper‐catalyzed reactions of alkynes have advanced significantly over the past few decades, and several useful reviews have been published on the chemistry of alkynes with copper metal 33–39 …”