Behavior of 1,3-Di(tert-butyl)-2,4-bis(tetramethylpiperidino)-1,3,2,4-diphospha- diboretane towards Boron Halides and Adduct Formation of a Bicyclo[1.1.0]diphosphadiboretane with Tris(pentafluorophenyl)borane [1]
AbstractWhile the diphosphadiboretane (tBuP=Btmp)2, 1, reacts with boron trihalides BX3 (X = Cl, Br, I) with BN cleavage producing a number of unidentifiable products, a new tricyclic BP ring system 2, containing B3P3, PB2C2 and C6 rings, results from the combination of PhBCl2 and 1. B-Chlorocatecholborane and 1 give access to the diborylphosphane 3, tmpBCl-PtBu-cat (cat = C6H4O2B). This shows that the selectivity of the reactions increases as the Lewis acidity of boron halide decreases. The structure of compounds 2 and 3 were determined by X-ray structure analysis. The bicyclic (tmpBP)2 4 forms no adducts with MeI, CF3SO2Me or Ph3C(SnCl5). However, it adds B(C6F5)3 to give 10, the first BX3 adduct of this bicycle that is fully characterized including its molecular structure.