172512-08-2Relevant academic research and scientific papers
Tri-tert-butylazadiboriridine: Ring Prolongation by the Action of Isonitriles, α-Bromolithioalkanes, and Azides
Luckert, Stefan,Eversheim, Ellen,Mueller, Matthias,Redenz-Stormanns, Burkhard,Englert, Ulli,Paetzold, Peter
, p. 1029 - 1036 (2007/10/03)
Isonitriles ArNC are 1,1-boroborated by the B-B bond of the azadiboriridine (-BR-BR-NR-) (1; R = tBu) to form the four-membered ring (2b; Ar = 2,6-C6H3Me2).Corresponding rings undergo cyclodimerization of the B-C=N chain to give the tricyclic products 6a,b when isonitriles RNC with the small ligands R = Me, Et are boroborated by 1.Two molecules of tBuNC open the B-B bond of 1; the resulting five-membered ring 7a may add excess tBuNC to yield 7a*2CNtBu (8).The results strongly support a mechanistic hypothesis set up for the multistep reaction of 1 and CO.The carbene units, which are present in the α-bromolithioalkanes , LiC(Br)H2, and LiC(Br)Me2, are also 1,1-boroborated by 1 to give the corresponding four-membered ring 2c, or by a 2:1 reaction to afford the five-membered ring 7b, or by a 1:1 reaction and subsequent rearrangement to yield the five-membered ring 7c.The nitrene units, which are present in the azides PhN3 and PhCH2N3, are also boroborated by 1; the diazadiboretidines 5b,c are formed with evolution of N2.The bis(diazadiboretidinyl)borane RB(N2B2R3)2 (5d) is the corresponding product from the reaction of RB(N3)2 with 1 in the ratio 1:2.The azide Me3SiN3 reacts differently yielding the N-boryl diazadiboretidine 5e and the iminoborane RBNR.The B-B bond length of 187.6 pm in 5e indicates a transannular bonding interaction.The products 5d, 5e, and 6a were characterized by a crystal structure analysis. - Keywords: Azadiboracyclobutanes / Azadiboracyclopentanes / Azadiboriridine, ring-opening of
