ISSN:
1434-1948
Keywords:
1,2-Diboraheterocycles
;
Carbon monoxide insertion
;
Isonitrile insertion
;
Dimerisation
;
Spiro insertion products
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The insertion of CO into the B-B bond of 1,2-bis(diisopropylamino)-2,5-dihydro-1H-1,2-diborole (1b) and 1,2-bis(diisopropylamino)-3-methylidene-1,2-diborolane (1c) leads to the dimeric spiro products 1,7,9,14-tetrakis(diisopropylamino)-6,13-dioxa-1,7,9,14-tetraboradispiro[4.2.4.2]tetradeca-2,10-diene (4b) and 1,7,9,14-tetrakis(diisopropylamino)bismethylidene-6,13-dioxa-1,7,9,14-tetraboradispiro[4.2.4.2]tetradecane (4c). Insertions of CO into the B-B bonds of the cyclic organo-1,2-diborane compounds 5, 6, and 7 are not observed. The reaction of 1b with tert-butyl isocyanide and 2,6-dimethylphenyl isocyanide in THF leads to the formation of the monomeric insertion products 1,3-bis(diisopropylamino)-2-tert-butylimino-1,3-diboracyclohex-4-ene (10b) and 1,3-bis-(diisopropylamino)-2-(2′,6′-dimethylphenylimino)-1,3-diboracyclohex-4-ene (11b). The treatment of 1cwith the isonitriles yields 2-tert-butylimino-1,3-bis(diisopropylamino)-4-methylidene-1,3-diboracyclohexane (10c) and 1,3-bis(diisopropylamino)-2-(2′,6′-dimethylphenylimino)-4-methylidene-1,3-diboracyclohexane (11c). The steric requirements of the isonitrile insertion products 10b, c and 11b, c prevent their dimerisation and rearrangement. 11b rearranges to 1-(diisopropylamino)-2-(diisopropylaminohydroxyboryl)-2-(2′,6′-dimethylphenylamino)-1-boracyclopent-3-ene (12b) upon reaction with water from sodium sulfate decahydrate. The compositions of the compounds are derived from the 1H-, 11B-, 13C-NMR data as well as from mass-spectral and C, H, N analyses. In the cases of of 4b and 12b they have been proven by X-ray structure analyses.
Type of Medium:
Electronic Resource
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