1,1‐Hydroborierung von Alkinen mit 6‐Aza‐ nido ‐decaboranen

1,1‐Hydroboration of Alkynes with 6‐Aza‐ nido ‐decaboranes [1] Alkynes ACCR′ (R′ = Me, Bu, t Bu, SiMe 3 ), that contain a mobile group A, like H or SiMe 3 , undergo hydroboration by 6‐aza‐ nido ‐decaboranes RNB 9 H 11 ( 1a‐c , R = H, Ph, PhCH 2 ) and 1,2‐migration of the group A, to give the corresponding 9‐(1‐alkenyl)‐6‐aza‐ nido ‐decaboranes RNB 9 H 10 (CH=CR′A) ( 2a‐h ). Ethenes AHC=CH 2 (A = SiMe 3 , SnBu 3 ) are hydroborated by 1a, b as well to form products of the type RNB 9 H 10 (CH 2 CH 2 A) ( 3a‐c ). The alkyne Me 3 SiCCH undergoes a hydroboration with 1b twice; the formation of (PhNB 9 H 10 ) 2 CHCH 2 SiMe 3 ( 4 ) proceeds by a 1,1‐ and a 1,2‐hydroboration step, apparently. The crystal structure analysis of (PhCH 2 )NB 9 H 10 [CH=CMe(SiMe 3 )] ( 2e ; space group Pl ) reveals a ( Z configuration of the ethene moiety.