Preparation of Di-, Tri-, and Tetra-Substituted Functionalized Ferrocenes via Magnesium Organometallics

Abstract

Ferrocenyl carboxylic acid deriVatiVes were metalated with TMPMgCl • LiCl, leading after reaction with electrophiles to 1,2-disubstituted ferrocenes. Further metalation of these disubstituted ferrocenes with TMPMgCl • LiCl afforded trisubstituted ferrocenes. A 1,2,3,4-tetrasubstituted ferrocene deriVatiVe could also be prepared in this way.

Reaction of N‐Heterocyclic Silylenes with Thioketone: Formation of Silicon–Sulfur Three (Si‐C‐S)‐ and Five (Si‐C‐C‐C‐S)‐Membered Ring Systems

“…Studies showed that ferrocene could be mono‐ or polymetalated by using mixed alkali metal–magnesium, –zinc, and –manganese bases 17. Another mixed lithium–magnesium base, TMPMgCl · LiCl (TMP = 2,2,6,6‐tetramethylpiperidino), proved suitable for the chemoselective metalation of derivatives bearing reactive functions (ester, nitrile, and carboxylic acid) when used in a polar solvent at temperatures around 0 °C 18. In search of alternative methods working at room temperature, we recently identified (TMP) 3 CdLi,19 prepared in situ from CdCl 2 · TMEDA and LiTMP (3 equiv.…”

Diastereoselective Deprotonative Metalation of Sugar‐Derived Ferrocene Esters Using Mixed Lithium–Cadmium Combinations

“…[17] Another mixed lithium-magnesium base, TMPMgCl·LiCl (TMP = 2,2,6,6-tetramethylpiperidino), proved suitable for the chemoselective metalation of derivatives bearing reactive functions (ester, nitrile, and carboxylic acid) when used in a polar solvent at temperatures around 0°C. [18] In search of alternative methods working at room temperature, we recently identified (TMP) 3 CdLi, [19] prepared in situ from CdCl 2 ·TMEDA and LiTMP (3 equiv. ), as an efficient reagent for the deprotonative metalation of ferrocene esters.…”

Regio‐ und chemoselektive Metallierung von Arenen und Heteroarenen mit gehinderten Metallamidbasen

“…[85,136] Die Magnesierung unter Verwendung von TMPMgCl·LiCl (2) [139] führt zu dem disubstituierten Ferrocen 127 in 67 % Ausbeute. [140] [140] Die Synthese von hoch funktionalisierten Indolen wird durch mehrfache Magnesierungen mit TMPMgCl·LiCl (2) an einfach zugänglichen, geschützten Anilinderivaten ermçglicht. [141] Folglich liefert die Reaktion des tetrasubstituierten geschützten Anilins 131 mit 2 (25 8C, 2 h) durch selektive Metallierung in Position 5 ein intermediäres Grignard-Reagens, das mit TsCN zu dem entsprechenden Benzonitril 132 umgesetzt wurde (80 % Ausbeute).…”