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

The ferrocene derivative (η 5 ‐Cp)Fe{η 5 ‐C 5 H 3 ‐1‐(ArNCH)‐2‐(CH 2 NMe 2 )} ( 1 ; Ar=2,6‐iPr 2 C 6 H 3 )) reacts diastereoselectively with LiR by carbolithiation and subsequent hydrolysis to give (η 5 ‐Cp)Fe{η 5 ‐C 5 H 3 ‐1‐(ArHNCHR)‐2‐(CH 2 NMe 2 )} ( 3 : R=tBu; 4 : R=Ph; 5 : R=Me) in high yields. For R=tBu, the organolithium derivative (η 5 ‐Cp)Fe{η 5 ‐C 5 H 3 ‐1‐(ArLiNCHR)‐2‐(CH 2 NMe 2 )} ( 2 ) was isolated. Compound 2 reacts with GeCl 2 ⋅dioxane and SnCl 2 to give the metallylene amide chlorides (η 5 ‐Cp)Fe{η 5 ‐C 5 H 3 ‐1‐(ArMNCHtBu)‐2‐(CH 2 NMe 2 )} 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 (η 5 ‐Cp)Fe{η 5 ‐C 5 H 3 ‐1‐(ArMNCHtBu)‐2‐(CH 2 NMe 2 )} [ 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 (η 5 ‐Cp)Fe{η 5 ‐C 5 H 3 ‐1‐(ArHNCHtBu)‐2‐(CH 2 NMe 2 )‐3‐SiMe 3 } ( 10 ).