Addition von Stannylenen an Iminoborane

Addition of Stannylenes to Iminoboranes Iminoboranes t BuB NR (R = t Bu, Mes: 1 a, b ) undergo aminostannation by the diaminostannylene Sn[N(SiMe 3 ) 2 ] 2 ( 2b ) to give (Me 3 Si) 2 N‐B( t Bu) = NR–Sn–N(SiMe 3 ) 2 ( 4a, b ). The stannylene 4 b remains monomeric in the crystal (space group P 2 1 / n ). The cyclic diaminostannylene [–Sn–N( t Bu)–SiMe 2 ‐N( t Bu)–] ( 3 b ), instead, simply adds the boranes 1 a, b across one of its Sn–N bonds to form the bicyclo[2.2.0]hexene‐type products 5a, b .