101078-06-2Relevant articles and documents
Novel Chelated Organodiboroxanes and Organoboroxins from Triorganoboroxins and Enolizable 1,3-Diketones
Koester, Roland,Angermund, Klaus,Sporzynski, Andrzej,Serwatowski, Janusz
, p. 1931 - 1952 (2007/10/02)
Trialkylboroxins (RBO)3 (1) react with enolizable 1,3-diketones (R'CO)2CH2 at ca. 20 deg C with fast degradation of the boroxin rings to give the monochelated diboroxanes 3 of the composition HOB(R)OB(R)OC(R')CHC(R')O in yields up to 85percent.The solid 3 with H-bridged bicyclic structures are in equilibrium with partially ring opened compounds in solution (1H, 11B, 13C, and 17O NMR data).From 1b with 2a or from triphenylboroxin (1c) with 2b the double chelated diboroxanes 2O are obtained. 1c reacts with 2a or 2b at >140 deg C under slow protolysis of the B-phenyl residues to form the single and double chelated boroxins 5 and 6 having the compositions R2B3O3(R'CO)2CH and RB3O32 . - 4,5, and 6 with fully or partially chelated boron atoms are stable up to >200 deg C. - The molecular structures of 4cb and 5ca were determined by X-ray analyses.