Weitere Reaktionen des Amino(imino)borans Me3Si(tBu)N*B*NtBu und des Alkyliden(amino)borans Me3Si(tBu)N=B=CHtBu

Further Reactions of the Amino(imino)borane Me3Si(tBu)N*B*NtBu and the Alkylidene(amino)borane Me3Si(tBu)‐N=B=CHtBuThe alkylidenetantalum complexes [tBuHCTaCl3(THF)2] (1b), [PhHCTaCl3(PMe3)2] (1c), and [tBuHCTa(CH2tBu)3] (1d) were treated with the amino(imino)borane Me3Si(t‐Bu)N*B*NtBu (2d). From 1b and 2d, the alkylidene(amino)borane Me3Si(tBu)NBCHtBu (7) is formed by metathesis. The 1:2 reaction of 1c with 2d gives the azadiboracyclobutane [–N(tBu)–B(X)–CHPh–B(X)–] [6d, XMe3Si(tBu)N]. The six‐membered ring compound [–N(tBu)BR–N(tBu)–SiMe2–CH2–TaR(CHtBu)–] (8, R=CH2tBu) is obtained from 1d and 2d; the product 8 crystallizes in the space group P 21/c. The borane 7 is attacked at the BC double bond by Et2NH, tBuCHO, and Me3SiN3 giving the diamino(neopentyl)borane 9 by protolysis, the oxaboracyclobutane 10 by [2 + 2] cycloaddition, and the azaboracyclopropane 11 by cycloaddition and elimination of N2, respectively.