Alkynylation of ferrocene by terminal alkynes. Part I. A simple one-step synthesis of ferrocenylacetylenes

Ferrocene reacts with terminal alkynes in the presence of copper and iron salts to give 1-ferrocenyl-2-R-alkynes (R – substituent). This direct cross-coupling of ferrocenyl and alkynyl moieties allows for the preparation of ferrocenyl substituted alkynes in one step directly from ferrocene and a terminal alkyne avoiding prior preparation of other derivatives of ferrocene. This new synthetic reaction does not require special conditions, is promoted by the action of common iron and copper salts, and tolerates the presence of functional groups in the alkyne.

Graphical abstractFerrocene reacts with terminal alkynes (I) in the presence of copper and iron salts to give 1-ferrocenyl substituted acetylenes (II) characterized by NMR and LDI studies. The reaction tolerates the presence of functional groups in alkyne and can be named a “direct alkynylation of ferrocene”.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Ferrocene reacts with terminal alkynes in the presence of copper and iron salts. ► The reaction gives 1-ferrocenyl substituted acetylenes. ► The presence of functional groups in alkyne is tolerated. ► This reaction can be named a “direct alkynylation of ferrocene”.