ISSN:
1434-1948
Schlagwort(e):
Boron
;
Small rings
;
Trifluoromethyl group
;
Crystal structure
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
1,1-Dimethyl-2,2-bis(trifluoromethyl)azoniaboratacyclopropanes, cyclo-(F3C)2B-CR1R2-NMe2 [R1 = R2 = C6H5 (2a); R1/R2 = C12H8 (2b); R1 = H, R2 = C6H5 (2c), 4-FC6H4 (2d), 3-FC6H4 (2e), 2-FC6H4 (2f), C6F5 (2g), iPr (2h), tBu (2i); R1 = Me, R2 = C(=O)OMe (2j), C(=O)OEt (2k)] have been obtained from (F3C)2BNMe2 (1) and diazomethanes R1R2CN2. In contrast to compound 2a, the B-N bonds of 2b-2k hydrolyze to form the zwitterionic species Me2NH-CR1R2-B(CF3)2OH (3b-3k). The diazoacetic acid esters HC(N2)C(=O)OMe and HC(N2)C(=O)OtBu react with 1 to form three-membered rings, which hydrolyze rapidly to form Me2NH-CR1R2-B(CF3)2OH [R1 = H, R2 = C(=O)OMe (3l), C(=O)OtBu (3m)]. F3CSiF3 reacts under elimination of CF2 with 1 to form the acyclic derivative (F3C)2BF-CF=NMe2 (4). The structures of 2a and 3ghave been investigated crystallographically. A nearly eclipsed conformation is found for the central B-C bond of 3g, which is 0.097(7) Å longer than the B-C bond length in the three-membered ring of 2a.
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
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