<i>N,N′</i>‐Dilithiobis(alkylamino)phenylborane als Synthesebausteine für viergliedrige Metallacyclen

N , N ′‐Dilithiobis(alkylamino)phenylboranes as Starting Materials for Four‐Membered Metallacycles Reactions of N,N′ ‐Dilithiobis(alkylamino)phenylboranes with tetrachlorides MCl 4 (M = Ge, Sn, Ti, Zr) produce the 4,4′‐spirobi(1,3‐dialkyl‐2‐phenyl‐1,3‐diaza‐2‐bora‐4‐metalla‐cyclobutane) derivatives 1a, 1b, 2b, 3a , and 3b . With diorganylmetal dihalides R 2 MX 2 (M = Sn, Zr; X = Cl, Br), the 1,3‐diaza‐2‐bora‐4‐metallacyclobutanes 2a and 4 are obtained. For 3a an X‐ray structure analysis has been performed.