ISSN:
0009-2940
Keywords:
Benzo-1,3,2-diphosphaborolanes
;
Benzo-1,3,2-diphosphaborolane dimmers
;
Benzo-1,4,2,3-diphosphadiborinanes
;
Rearrangement reaction
;
Pentacarbonyl chromium complexes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A series of benzo- 1,3,3-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 (4f) 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(iPr)Li]2 is allowed to react with B2(NMe2)2Cl2, the benzo-1,4,2,3-diphosphadiborinane 13 is obtained, together with its rearrangement product 2-bis(dimethylamino)borylbenzo-1,3,2-diphosphaborolane 14 which dimerizes to (14)2. - In contrast, the almost planar ring of the 2,3-dimesitylbenzo-1,4,2,3-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-1,5,2,3,4-diphosphatriborepane 18 forms readily 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.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19971301120
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