199680-08-5Relevant academic research and scientific papers
Studies on benzo-1,3,2-diphosphaborolanes, benzo-1,4,2,3-diphosphadiborinanes and benzo-1,5,2,3,4-diphosphatriborepanes
Kaufmann, Bernhard,Jetzfellner, Ralf,Leissring, Elke,Issleib, Kurt,Noeth, Heinrich,Schmidt, Martin
, p. 1677 - 1692 (1997)
A series of benzo-1,3,2-diphosphaborolanes C6H4(PR)2BR′ (R = H, iPr, SiMe3; R′ = R2N, R) has been prepared by several routes and characterized by spectroscopic and - in part - by X-ray diffraction methods. They feature pyramidal P atoms with the substituents in antiperiplanar positions. The P atoms act as coordination sites for the (CO)5Cr fragment. In contrast to the R2N-bearing benzo-1,3,2-diphosphaborolanes, the derivative C6H4(PH)2BCMe3 (4i) dimerizes by additional B-P bond formation to produce a pentacyclic system (4f)2. - The reaction of C6H4(PHNa)2 with B2(NMe2)2Cl2 in THF/hexane yields the acyclic phosphanylborane Me2NB(PH-C6H4PH2)2 (15). However, if C6H4[P(/Pr)Li]2 is allowed to react with B2(NMe2)2Cl2, the benzo-1,4,2,3-di-phosphadiborinane 13 is obtained, together with its rearrangement product 2-bis(dimethylamino)borylbenzo-l,3,2diphosphaborolane 14 which dimerizes to (14)2. -In contrast, the almost planar ring of the 2,3-dimesitylbenzo1,4,2,3-diphosphadiborinane (16) possesses P and B atoms with a planar geometry. Short B-B and B-P bonds suggest that this new heterocycle can be regarded as a 6π electron system. Moreover, the benzo-l,5,2,3,4-diphosphatriborepane 18 forms readily from C6H4(PHNa)2 and Br(Me2N)B-B(N-Me2)-B(NMe2)Br to give a tub-shaped seven-membered C2B3P2 ring system with the P atoms in a pyramidal and the B atoms in a planar environment. WILEY-VCH Verlag GmbH,sss 1997.
