Propargylic sulfides

The combined solutions were dried over magnesium sulfate and subsequently concentrated in a water-pump vacuum. Distillation of the residue through a 30-cm Vigreux column gave the silylated propargyl sulfide, b.p. 65°C/18 mmHg, n ... 

Siiylcupration also works witli 1-aminoalkynes [70], propargyl sulfides [71], prop-argyl amines [14a, 72] - where it bas been exploited in tlie syntliesis of saturated and Linsaturated j -s dyl-a-amino acids iSdieme 3.17) - and propargyl ediers, where... 

A more direct access to the unstable and non isolated sulfonium ylides 58a- c is the reaction of diisopropyl diazomethylphosphonate 57 with allylic sulfides, catalyzed by Cu(II), Rh(II) [39], or ruthenium porphyrins.[40] For example, the a-phosphorylated y,d-unsaturated sulfides 59-61 are obtained through the [2,3] -sigmatropic rearrangement of 58a-c. This method allows the use of a greater variety of starting allylic sulfide substrates, such as 2-vinyl tetrahydrothiophene, or propargylic sulfides (Scheme 15). 

An example of an iron-catalyzed C-C bond formation reaction was reported in 2001 [89]. Treatment of propargyl sulfides 87 with trimethylsilyldiazomethane in the presence of 5 mol% FeCl2(dppb) gave substituted homoallenylsilanes 88 in good to moderate yields (Scheme 3.43). The silanes 88d and 88e, which bear two centers of chirality, were obtained as 1 1 mixtures of diastereomers. Slight diastereoselectivity (2 1) was seen for the formation 88f, which is an axially chiral allene with a sterogenic center. 

An intriguing approach to nitrogen-substituted allenes such as 253 was reported by van Vranken and co-workers (Scheme 8.67) [148]. Iron(II)-catalyzed sulfimidation of propargyl sulfides 252 and subsequent [2,3]-sigmatropic rearrangement furnish 253 in moderate to good yields. 

Fuchigami and co-workers utilized the regioselective anodic fluorination of aryl propargyl sulfides 301 for the preparation of fluorinated alkyne intermediates, which were subsequently isomerized by sodium ethoxide to furnish 1-fluoro-l-arylthioallenes 302 (Scheme 8.80) [166]. 

Por metallocupration of propargyl sulfides see A. Casaeini, B. JoussEAUME, D. Lazzaei, E. 

Dilithiation of Benzylacetylene and Methyl Propargyl Sulfide in EtjO... 

Methyl Propargyl Sulfide from Sodium Methanethiolate and Propargyl Chloride CH3OH, h2o... 

Vinyl propargyl sulfide may undergo explosive decomposition upon heating at temperatures above 70 C [2). 

The isomerization reactions of pentafluorophcnyl and heptafluoro-2-naphthyl propargyl sulfides have been studied under a variety of conditions.38 For example, the naphthyl sulfide rearranges to the fluoromethyl derivative 46 in 81 % yield when distilled at 360 C in vacuo through a glass tube packed with quartz wool. 

Cleavage of a C—S bond to give a thiocarbonyl derivative can be induced thermally, photochemically or by appropriate reagents1. Thermolysis has been carried out for mechanistic studies rather than for synthetic purposes and has been applied to the preparation of propynethial starting from propargyl sulfide in a flow system320 (equation 54). 

Recently, Van Vranken s group demonstrated that propargyl sulfides are also able to undergo this transformation upon treatment with (dppe)FeCl2, affording N-allenylsulfenimides (Scheme 3.57) [173]. 

The iron-catalyzed reaction of propargyl sulfides 66 and trimethylsilyldiazomethane 67 delivers allenyl a-silyl sulfides 68 [44]. 

Very recently, Davies and coworkers have reported a silver-catalyzed Doyle-Kirmse reaction of ally lie and propargylic sulfides with ethyl diazophenylacetate (35). A selection of examples was investigated providing the rearranged products, either homoallylic thioethers (76 —> 77, Scheme 8.14a) or allenyl thioethers (78 —> 79, Scheme 8.14b) in good yields, and with good overall scope.40... 

It is noteworthy that the addition of thiols to form propargylic sulfides is not catalysed by the neutral complex [Cp RuCl(p2-SR)2RuCl(Cp )], but requires the utilization of a cationic precursor such as [Cp RuCl(p2-SMe)2Ru(Cp )(H20)]0Tf [85]. With this catalytic system,propargylic alcohols bearing an internal triple bond are also transformed into propargylic sulfides, which indicates that in this special case, the reaction does not involve a ruthenium allenylidene as an active species. 

Reaction of 2-thienyl propargyl sulfide (98) in HMPA led to 2i/-thieno[2,3-Z ]thiopyran (99) (Equation (21)). Claisen type rearrangements are involved in the reaction, which proceeded in excellent yields. The reaction is also a useful method for the preparation of 57/-thieno[3,2-6]thio-pyran and methyl derivatives of these compounds <69RTC732,72RTC785). 

Trisubstituted furans were obtained via an unprecedented 1,4-shift of the sulfanyl group of allenyl sulfides in high yields employing ruthenium complexes as catalyst, as depicted below. Furan products can also be provided in a one-pot reaction from a-diazocarbonyls and propargyl sulfide using both rhodium- and ruthenium-complexes or only a ruthenium-complex as catalyst <07AGE1905>. 

The [2,3]sigmatropic rearrangement of sulfonium ylide (24) derived from rhodium-catalyzed decomposition of ethyl 3,3,3-trifluoro-2-diazopropanoate (23) in the presence of propargyl sulfide (22a) affords the corresponding functionalized CF3-containing carboxylic ester sulfide (25a). The latter was... 

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