2-Benzothiazolyl lithium, reaction with

Benzothiazolyl-lithium (70), prepared from benzothiazole and n-butyl-lithium in THF at —80 C, reacts in situ with the appropriate chlorosilanes to afford mono- (71) and di-(2-benzothiazolyl)silanes (72) (see also these Reports, Vol. 2, p. 672). The latter are also formed in higher yields from (71) by a novel trans-silylation reaction. The assigned structures of the silylbenzothiazoles are in agreement with their observed n.m.r. spectra. The compounds are colourless, stable substances, of considerable reactivity. 

Reaction of BTSP with 2-benzothiazolyl allyl lithium proceeds in a regioselective and stereoselective manner leading to the silyloxylation and the trans methylation product (Scheme 9). 

The chemistry of pyridylphosphines has been reviewed. Further studies have appeared of the reactions of phosphines bearing 2-pyridyl or 2-benzothiazolyl substituents with butyl-lithium, which result in the formation of biaryl coupling products via an initial nucleophilic attack at phosphorus. A study of the de-diazoniation of arenediazonium salts using triphenylphosphine (and trialkylphosphites) indicates that the reactions proceed via a radical-chain mechanism, initiated by single electron transfer from the phosphine to the diazonium salt, to give... 

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