20875-42-7Relevant academic research and scientific papers
Stereo-recognizing transformation of (E)-alkenyl halides into sulfides catalyzed by nickel(0) triethyl phosphite complex
Yatsumonji, Yasutaka,Okada, Orie,Tsubouchi, Akira,Takeda, Takeshi
, p. 9981 - 9987 (2007/10/03)
(E)-Alkenyl halides were transformed into (E)-alkenyl sulfides by the nickel(0) triethyl phosphite complex-catalyzed reaction with thiols, whereas (Z)-alkenyl halides gave alkynes under the same reaction conditions. Aryl halides were also transformed into aryl sulfides using the same reagent system.
The Formation of Vinyl Sulfides by the Cleavage of the Carbon-Sulfur Bond in Dithioacetals with CuCl2
Oida, Tatsuo,Tanimoto, Shigeo,Ikehira, Hideyuki,Okano, Masaya
, p. 959 - 960 (2007/10/02)
The elimination of arene- and alkanethiol from diaryl and dialkyl dithioacetals, in the presence of copper(I) or copper(II) salt plus tertiary amine, to produce the corresponding aryl and alkyl vinyl sulfides, respectively, has been studied.The employment of a combination of 2 mol equiv. of CuCl2 and 2 mol equiv. of N,N-diisopropylethylamine is most favorable.
Heterocyclisation radicalaire de thiols acetyleniques
Dupuy, Claude,Crozet, Michel-Pierre,Surzur, Jean-Marie
, p. 361 - 373 (2007/10/02)
Photolysis of pent-4-yne-1-thiol 1 leads to a mixture of thiacyclohex-2-ene 2, 2-methylenethiacyclopentane 3 and 2-methylthiacyclopent-2-ene 4 with overall yield of up to 60 percent.Compound 2 is always amply predominant and can, according to the experimental conditions, make up to 100 percent of the mixture.Compounds 2 and 3 are assumed to derive from the thiyl radical, which adds essentially to the terminal position of the triple bond.The addition reaction is reversible, with the radical leading to compound 3 (five-membered ring) being kinetically favoured, as shown by temperature and concentration effects on the ratio 2/3.The use of deuteriated thiols shows the hydrogen transfer step to be irreversible and to proceed from the thiol itself.This study has been extended to the substances HCC(CH2)nSH 1a (n = 2 to 6).Again, we obtained essentially or exclusively the compound 2a resulting from preferential addition to the terminal position of the triple bond.The same substrates thus lead regioselectively either to the heterocycles 2a or to the heterocycles 3a, according to whether formation of the thiyl radical or of the thiolate anion is favoured.Therefore these two processes are synthetically complementary.The introduction of a heteroatom Y into the chain does not seem to entail any important modification of the course of the radical cyclization reaction itself.Indeed, the substances HCCCH2Y(CH2)2SH 1b (Y = O, S, NR) again lead essentially to substances 2b.However, a new heterocyclic substance 4b is formed, the origin of which is attributed to the isomerization of the triple bond of the initial substrate 1b, facilitated by the heteroatom Y.An alkyl group in the terminal position of the triple bond, on the other hand, entirely modifies the regioselectivity of the reaction.The substrates RCC(CH2)nSH 1a (R = Me, Ph; n = 2 to 5) lead essentially to product 3a, resulting from addition on the non-terminal position of the triple bond.This trend is particularly clear when R = Ph, a fact attributed to the benzylic character of the intermediate radical : only compounds 3a are then isolated, with excellent yields (86 percent for n = 3, 89 percent for n = 4).Nevertheless, the results of this exploratory study cannot be used in a quantitative manner to establish regioselectivity rules regarding intramolecular addition to an acetylenic system.This remark especially stems from a more elaborate study of the by-products formed by photolysis of pent-4-yne-1-thiol 1.In some cases an isomeric heterocyclic product 4 is formed which can be showed not to result from isomerization of 2 and to result only partially from isomerization of 3.This led us to suggest that it is formed by isomerization of the initial acetylenic thiol 1 to the isomeric allenic thiol.On the other hand, even in the high dilution conditions used, we isolated polymers and dimers with yields of 20 to 60 percent.The dimers, which could be analyzed, are a mixture, often complex but essentially composed of substances 5 (widely predominant) and 6.These products could arise from regioselective add...
