ISSN:
0947-6539
Schlagwort(e):
ab initio calculations
;
barbaralanes
;
borabarbaralanes
;
Cope rearrangement
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The reaction of MgCOT(thf)x with tBuBF2 or PhBCl2 affords the first 9-borabarbaralanes 2 (C8H8BR, a: R = tBu; b: R=Ph). With the aminoboron dihalides BCl2NiPr2 and BCl2N(SiMe3)tBu 9-borabicyclo[4.2.1]-nona-2,4,7-trienes 3 (a: R=NiPr2, b: R=N(SiMe3)tBu) and the trans-9-borabicyclo[4.3.0]nona-2,4,7-triene 4 are obtained. The bicyclic compounds 3a and 3 b are converted into 9-borabarbaralanes 2c and 2 d, respectively, by irradiation in solution as well as by heating. All 9-borabarbaralanes 2 are fluxional in solution. In the crystalline state, the B-phenyl derivative 2b displays a well-ordered van der Waals crystal structure. The theoretical prediction that the degenerate Cope rearrangement in barbaralanes will be retarded by π-acceptor groups in the 9 position has been verified. Quantum chemical calculations employing density functional theory support and help interpret the experimental findings. The isoelectronic 9-barbaralyl cations, in contrast, have such high Cope barriers that other rearrangement pathways are followed instead.
Zusätzliches Material:
1 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/chem.19960020416
Permalink
