C–H Functionalization of BN-Aromatics Promoted by Addition of Organolithium Compounds to the Boron Atom

Three new, substituted, nido carboranes, 7,8-Ph2-10-(SMe2)-7,8-nido-C2B9H10 (1a), 7,8-Ph2-10- (SMeEt)-7,8-nido-C2B9H10 (1b) and 7,8-Ph2-10-(SEt2)-7,8-nido-C2B9H10 (1c) have been synthesised and characterised, including a crystallographic study of the first. Deprotonation of 1a followed by treatment with (MeCN)2(CO)2MoBr(η-C3H5) at 0 °C affords the non-icosahedral 1,2-Ph2-4-(SMe2)-5-(η-C3H5)-5,5-(CO)2-5,1,2-closo-MoC2B9H8 (2a), which on subsequent warming transforms into icosahedral 2,8-Ph2-5-(SMe2)-1-(η-C3H5)-1,1-(CO)2-1,2,8-closo- MoC2B9H8 (3a). It is argued that under the conditions of these rearrangements the B-S bond is likely to remain intact, and consequently that the identity of the SMe2-labelled boron atom in 3a affords useful experimental information on the course of the isomerisation.

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Reaction of organolithium compounds with 1-substituted 2,4,6-triphenylpyridinium perchlorates

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19891880 ◽

1989 ◽

Vol 54 (7) ◽

pp. 1880-1887 ◽

Cited By ~ 3

Author(s):

Marián Schwarz ◽

Josef Kuthan

Keyword(s):

Visible Range ◽

Molecular Spectra ◽

Organolithium Compounds ◽

Phenylmagnesium Bromide

The reaction of organolithium compounds with 1-substituted 2,4,6-triphenylpyridinium perchlorates Ia-Ic produces mixtures of 1,4-dihydropyridines IIa-IIe and 1,2-dihydropyridines IIIa-IIIe. Analogous reactions of phenylmagnesium bromide with compounds Ia-Ic proceed with very low conversions (less than 1%). Photochromism in visible range is observed only with the compounds II which have two aromatic substituents at 4-position, whereas compounds III and IId show no visible photochromism. The molecular spectra of the compounds newly prepared are discussed.

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PREPARATION OF C14-LABELLED ACIDS FROM C14O2 AND ARYL LITHIUM COMPOUNDS

Canadian Journal of Biochemistry and Physiology ◽

10.1139/o59-162 ◽

1959 ◽

Vol 37 (12) ◽

pp. 1439-1446 ◽

Cited By ~ 6

Author(s):

A. C. Neish

Keyword(s):

Benzoic Acid ◽

Barium Carbonate ◽

Grignard Reagents ◽

Similar Sequence ◽

Butyl Lithium ◽

Organolithium Compounds ◽

Lithium Compounds

A simplified technique was developed for carbonation of Grignard reagents or organolithium compounds, with C14O2 generated from barium carbonate. 3,4-(Dibenzyloxy)-bromobenzene was treated with n-butyl lithium in ether and then with C14O2 to give 3,4-(dibenzyloxy)-benzoic acid-carboxyl-C14. The yield was 74% based on barium carbonate. 2,6-Dichlorobenzoic acid-carboxyl-C14 (yield 77%) and 3,5-dichlorobenzoic acid-carboxyl-C14 (yield 76%) were prepared from the corresponding dichlorobromobenzenes by a similar sequence of reactions. Attempts to synthesize 2,4- and 2,5-dichlorobenzoic acids by this route gave poor yields of unidentified acids, from which the expected products could not be isolated.

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