Publication Date:
2011-09-28
Description:
The reaction of the aminohaloboranes (Me 2 N)( R )B X ( 1 ) ( a : R = Ph, X = Cl; b : R = Me, X = Br; c : R = i Pr, X = Cl) with the di-Grignard reagent (BrMg) 2 CH 2 in ethyl ether/benzene mixtures afforded the diborylmethanes [(Me 2 N)( R )B] 2 CH 2 ( 2 ) ( a : R = Ph; b : R = Me; c : R = i Pr), which were subsequently converted into the corresponding bis(chloroboryl)methanes [(Cl)( R )B] 2 CH 2 ( 3 ) ( a : R = Ph; b : R = Me; c : R = i Pr). Base-assisted cyclocondensation of 3a – c with 1,2-diisopropylhydrazine afforded 1,2-diisopropyl-1,2-diaza-3,5-diorgano-3,5-diborolidines ( 4 ) ( a : R = Ph; b : R = Me; c : R = i Pr). Derivative 4a was deprotonated by potassium bis(trimethylsilyl)amide to give (1,2-diisopropyl-1,2-diaza-3,5-diphenyl-3,5-diborolidinyl)potassium ( 5 ). Attempts to introduce a halogen atom to the carbon bridge between the two boron atom by treating 5 with either iodine or 1,2-dibromoethane failed. Instead, bis(1,2-diisopropyl-1,2-diaza-3,5-diphenyl-3,5-diborolidinyl) (C-C) ( 6 ) was formed. In contrast to this, C-silylation of the heterocycle to give 7 was effected by reaction of salt 5 with trimethylsilyl chloride. Similarly, treatment of HgCl 2 with two molar equivalents of 5 gave rise to the formation of bis(1,2-diisopropyl-1,2-diaza-3,5-diphenyl-3,5-diborolidinyl)mercury ( 8 ). The novel compounds were characterized by elemental analyses and various spectroscopic methods ( 1 H-, 11 B{ 1 H}-, 13 C{ 1 H} NMR, MS). The molecular structures of 4a and 6 – 8 were elucidated by X-ray diffraction analyses.
Print ISSN:
0044-2313
Electronic ISSN:
1521-3749
Topics:
Chemistry and Pharmacology
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