N-Functionalized Ferrocenes: Subvalent Group XIV Element Chlorides and tert-Butyllithium-Induced C-C Bond Cleavage under Mild Conditions

Bastian Nayyar; Hazem Alnasr; Wolf Hiller; Klaus Jurkschat

doi:10.1002/anie.201800128

N-Functionalized Ferrocenes: Subvalent Group XIV Element Chlorides and tert-Butyllithium-Induced C-C Bond Cleavage under Mild Conditions

Angew Chem Int Ed Engl. 2018 May 4;57(19):5544-5547. doi: 10.1002/anie.201800128. Epub 2018 Apr 14.

Authors

Bastian Nayyar¹, Hazem Alnasr¹, Wolf Hiller¹, Klaus Jurkschat¹

Affiliation

¹ Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44227, Dortmund, Germany.

PMID: 29450955
DOI: 10.1002/anie.201800128

Abstract

The ferrocene derivative (η⁵ -Cp)Fe{η⁵ -C₅ H₃ -1-(ArNCH)-2-(CH₂ NMe₂ )} (1; Ar=2,6-iPr₂ C₆ H₃ )) reacts diastereoselectively with LiR by carbolithiation and subsequent hydrolysis to give (η⁵ -Cp)Fe{η⁵ -C₅ H₃ -1-(ArHNCHR)-2-(CH₂ NMe₂ )} (3: R=tBu; 4: R=Ph; 5: R=Me) in high yields. For R=tBu, the organolithium derivative (η⁵ -Cp)Fe{η⁵ -C₅ H₃ -1-(ArLiNCHR)-2-(CH₂ NMe₂ )} (2) was isolated. Compound 2 reacts with GeCl₂ ⋅dioxane and SnCl₂ to give the metallylene amide chlorides (η⁵ -Cp)Fe{η⁵ -C₅ H₃ -1-(ArMNCHtBu)-2-(CH₂ NMe₂ )} 6 (M=GeCl) and 7 (M=SnCl), respectively, which each contain three stereogenic centers. The potential of 7 as a ligand in transition-metal chemistry is demonstrated by formation of its complex (η⁵ -Cp)Fe{η⁵ -C₅ H₃ -1-(ArMNCHtBu)-2-(CH₂ NMe₂ )} [9, M= Sn(Cl)W(CO)₅ ]. Treatment of 3 with tert-butyllithium at room temperature causes an unprecedented carbon-carbon bond cleavage whereas under kinetic control, lithiation at the Cp-3 position takes place, which leads to the isolation of (η⁵ -Cp)Fe{η⁵ -C₅ H₃ -1-(ArHNCHtBu)-2-(CH₂ NMe₂ )-3-SiMe₃ } (10).

Keywords: C−C bond cleavage; ferrocenes; germanium; lithium; tin.