Weitere Reaktionen des Amino(imino)borans Me 3 Si( t Bu)N*B*N t Bu und des Alkyliden(amino)borans Me 3 Si( t Bu)N=B=CH t Bu

Further Reactions of the Amino(imino)borane Me 3 Si( t Bu)N*B*N t Bu and the Alkylidene(amino)borane Me 3 Si( t Bu)‐N=B=CH t Bu The alkylidenetantalum complexes [ t BuHCTaCl 3 (THF) 2 ] ( 1b ), [PhHCTaCl 3 (PMe 3 ) 2 ] ( 1c ), and [ t BuHCTa(CH 2 t Bu) 3 ] ( 1d ) were treated with the amino(imino)borane Me 3 Si( t ‐Bu)N*B*N t Bu ( 2d ). From 1b and 2d , the alkylidene(amino)borane Me 3 Si( t Bu)NBCH t Bu ( 7 ) is formed by metathesis. The 1:2 reaction of 1c with 2d gives the azadiboracyclobutane [–N( t Bu)–B(X)–CHPh–B(X)–] [ 6d , XMe 3 Si( t Bu)N]. The six‐membered ring compound [–N( t Bu)BR–N( t Bu)–SiMe 2 –CH 2 –TaR(CH t Bu)–] ( 8 , R=CH 2 t Bu) is obtained from 1d and 2d ; the product 8 crystallizes in the space group P 2 1 / c . The borane 7 is attacked at the BC double bond by Et 2 NH, t BuCHO, and Me 3 SiN 3 giving the diamino(neopentyl)borane 9 by protolysis, the oxaboracyclobutane 10 by [2 + 2] cycloaddition, and the azaboracyclopropane 11 by cycloaddition and elimination of N 2 , respectively.