ISSN:
0009-2940
Keywords:
1,2,3,4-Diazadiboretidines
;
Oxadiazadiborolidines
;
Triazadiborolidines
;
Diazadiboracyclohexanes
;
Tetraazadiboracyclohexanes
;
1,2,5,6,3,4,7,8-Tetraazatetraborocane
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
1,2,3,4-Diazadiboretidines: Reactions of a Novel Class of Unsaturated Boron-Nitrogen Four-Membered Rings1,2,3,4-Diazadiboretidines [=B(tBu)-B(tBu)=NR-NR=] (R=Et, iPr: 2a, b) belong to the hitherto unknown class of head-head isomers of the known 1,3,2,4-diazadiboretidines (1). They are formed from the diborane(4) Cl-B(tBu)-B(tBu)-Cl and the hydrazines RHN-NHR in the presence of NEt3 via the partially unsaturated four-membered rings [-B(tBu)Cl-B(tBu)=NR-NHR-] (4a, b), which are transformed into 2a, b by the abstraction of HCl by means of the base LiNC9H18. Whereas the pure products 2a, b are instable, solutions of 2a, b in alkanes can be handled at 0°C without considerable decomposition. Reaction of 2a, b with the amine oxide Me3NO leads to insertion of an O atom, reaction with diazoalkane tBuCR′N2 (R′ = H, Me) to insertion of its β-N atom, and reaction with the azide PhCH2N3 to insertion of a nitrene N atom into the B-B bond of 2a, b with formation of five-membered rings 5a, b or 6a, b or 7a, b, respectively. Six-membered rings 8a, 9a, 10a, respectively, are the products of the insertion of the C≡C unit of 3-hexyne, the N=N unit of EtO2C-N=N-CO2Et, or the unsaturated C atoms of two molecules of C≡NtBu into the B-B bond of 2a. The condensation of the diaminodiborane(4) Cl-B(NMe2)-B(NMe2)-Cl with the hydrazine EtHN-NHEt in the presence of NEt3 yields the corresponding eight-membered ring [-B(NMe2)-B(NMe2)-NEt-NEt-]2 (11), which crystallizes in a twist conformation with symmetry group D2.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921251210
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