Claude Montginoul

Preparation and chemistry of new unsymmetrically substituted tetrachalcogenofulvalenes bearing CN(CH2)2X and HO(CH2)2X groups (X = S or Se)

Several unsymmetrically substituted TTFs bearing the S(CH2)2CN protecting group have been prepared by standard cross coupling in triethyl phosphite from the key intermediate 4,5-bis(2′-cyanoethylsulfanyl)1,3-dithiol-2-one 1 and an appropriate 1,3-dichalcogenole-2-chalcogenone, 2–8. TTFs 10, 11 and 12 of type I have been obtained in satisfactory yields (30–60%) and those (13,14) of type II in low yields (10 and 19%) as a result of differences in the reactivity of the species involved.Pseudo-Wittig condensations from the key triphenylphosphonium salt 15 have allowed considerable improvement in the synthesis of 13 (70% yield) and 14 (57% yield).The diselena analogue of 1, 21 has also been obtained. Its derivative 22, a new tetrakis(alkylselena) functionalised TTF, has been isolated in fair yield (69%). Its deprotection in a basic medium followed by a subsequent alkylation has led to BEDSe-TTF 23 (40%). Finally, the same sequence of deprotectionrealkylation carried out from unsymmetric species 10 and 12 has successfully been used in a high yield preparation of the corresponding new functionalised TTFs bearing two hydroxyethyl groups.

Polymérisation radicalaire vivante du mma en présence de dérivés piperidino-dithiocarbamates comme photoiniferters

Radical polymerizations of methyl methacrylate were carried out in the presence of photoiniferters (RDC) containing a piperidino-dithiocarbamate group. The effects of the structure of the RDC on the photopolymerization in the presence or absence of a transfer agent such as tetraethylthiuram disulfide (TD) were investigated. The influence of the presence of a transfer agent (TD) on the living character and the control of the polymerization were also discussed.

Étude de la coupure des liaisons o‐si d'éthers siliciés du type en présence d'agent nucléophile et/ou d'acide

We report a study on the hydrolytic instability of the oxygen-silicon bond of the following compounds: p-tert-butyldimethylsilyloxytoluene, p-trimethylsilyloxytoluene and poly(p-trimethylsilyloxystyrene). The instability occurs in an acidic media: HCl, H−2SO4, CF3CO0H, BF3 or in presence of a salt: KPF6, KAsF6, KSbF6, NaBF4, [CH3(CH2)3]4NF, [CH3(CH2)3]4NBF4, [CH3(CH2)3]4NPF6, [CH3(CH2)3]4N AsF6, [CH3(CH2)3]4NSbF6. A mixture containing both an acid and a salt from those previously discussed can also be used. A number of representative examples is presented. The tert-butyldimethylsilylether derivatives are much more stable than the trimethylsilylethers. It is shown that the rate of reaction is dependent on the nucleophilicity of anion used in these salts. This simple procedure undoubtedly extends the scope for a preparation of organosilicon resists.