Coordination chemistry of perhalogenated cyclopentadienes and alkynes. XXVIII [1] new high-yield synthesis of monobromoferrocene and simplified procedure for the synthesis of pentabromoferrocene. Molecular structures of 1,2,3-tribromoferrocene and 1,2,3,4

Monobromoferrocene (1) was obtained in 95% yield from ferrocene via lithiation with tert-BuLi/KO-tert-Bu and bromination with dibromotetrachloroethane. Starting from 1 mixtures of 1,2-dibromoferrocene (2) and apparently unreacted 1 (ranging from 80:20 to 50:50, depending on the reaction conditions) can be obtained via a lithiation- zincation- bromination sequence. These mixtures can be transferred directly with a tenfold excess of Lithium-tetramethylpiperidinide, followed by bromination with 1,1,2,2-tetrabromoethane to pentabromoferrocene (3), in an overall yield of 36% starting from ferrocene. The molecular structures of 3 and of 1,2,3-tribromoferrocene (4) have been determined by X-Ray diffraction.

Graphical abstractA new high-yield synthesis of monobromoferrocene and an optimized one-pot procedure fort the preparation of pentabromoferrocene have been developed. The crystal structure determinations of 1,2,3-tribromoferrocene and pentabromoferrocene are reported.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New high-yield synthesis of monobromoferrocene. ► Optimized one-pot procedure for the preparation of pentabromoferrocene. ► Crystal structure determinations of 1,2,3-tribromoferrocene and pentabromoferrocene.