Allyl thio-ether

Thio-ethers.— Ethers derived from the unsaturated hydrocarbons are known but are not important. The corresponding sulphur compounds, viz., the thio-ethers, are, however, of considerable importance and are represented by a commonly occurring substance. The thio-ether related to allyl alcohol is known as allyl thio-ether, or, also as allyl sulphide. It is made, like the thio-ethers of the saturated series, by treating the iodide of the hydrocarbon with potassium sulphide. 

These include copolymers of propylene sulphide with 3-10% of allyl glycidyl thioether and which may be considered as a thio-analogue of the propylene oxide-allyl glycidyl ether rubber briefly mentioned in Section 19.5 ... 

Among phosphonate esters (170) used in olefin synthesis were those with R = S-CeHi-Br-/ , S02 C6H4-Br-A CO-NHR, and S CHa CEi-XHa. The allyl vinyl thio-ethers (171) obtained using the last of these gave a-allyl-aldehydes on pyrolysis in the presence of red mercuric oxide. 

Chelotropic addition of dichlorocarbene to bornadiene gave (200 X = C1) whereas with difluorocarbene the, yyn-adduct was favoured over the anh-adduct (200 X = F) (cf. Vol. 3, p. 59). A thio-Claisen rearrangement has been reported with the allylic enethiolic ether of thiocamphor. Flash thermolysis of allyl exo-2-bornyl sulphide to thiocamphor and propene has been examined. 

The nucleophilicity of sulfur and its ability to stabilize a-carbanions provide sulfur compounds with unique opportunities for sigmatropic processes consecutive rearrangements are no exception. The formation of salt (140) via Sn2 alkylation of ( )-2-butenyl bromide (139) followed by deprotonation leads to the intermediate allyl vinyl ether (141) which, under the conditions of the deprotonation, undergoes a thio-Claisen rearrangement to afford thioamide (143 Scheme 10). Thermolysis of (143) at elevated temperature affords the Cope product (142) in addition to some of its deconjugated isomer. Several unique characteristics of the thio-Claisen sequence should be noted first, the heteroatom-allyl bond is made in the alkylation step, this connection teing not notrtudly practised in the parent Claisen reaction ... 

The (S)-lactone acid 1, obtained from L-glutamic acid by nitrous acid deamination, was converted to the acid chloride, then treated with excess diazomethane followed by hydrogen iodide to yield the keto-lactone 2. Amidation occurred quantitatively to give the partially racemized amide 3, which was purified by repeated recrystallizations. The vicinal diol resulting from reaction with excess methylmagnesium iodide was protected as the acetonide 4. An isomeric mixture of olefins (Z , 26 74) was obtained from the subsequent Wittig reaction. Reduction followed by separation on silver nitrate coated silica gel gave the (Z)-and ( )-alcohols in 20% (6) and 61% (5) yield, respectively. Conversion of the (S)-( )-alcohol (5) to the chloride then afforded the thioether (7) on reaction with sodium phenylsulfide. The thio ether anion was formed by treatment with n-butyllithium. Alkylation with the allylic chloride" (8), followed by removal of sulfur, then yielded the diene 9, which was converted in several steps to (/ ) (-t-)-10,11 -epoxy famesol. 

The first report found in this context is a contribution by Hurd and Greengard [1]. In 1930, they attempted the pyrolysis of allyl aryl sulfides (at 207-240 °C), in analogy to reported examples with ethers. They claimed the formation of 2-allyl thio-... 

Replacement of the oxygen atom in the allyl vinyl ether structural motif of a Claisen rearrangement with a sulfur atom describes the thio-Claisen rearrangement. " The reaction is faster as compared to the parent oxygen-... 

Me3SiCH2CH=CH2, TsOH, CH3CN, 70-80°, 1-2 h, 90-95% yield. " This silylating reagent is stable to moisture. Allylsilanes can be used to protect alcohols, phenols, and carboxylic acids there is no reaction with thio-phenol, except when Cp3S03H is used as a catalyst. The method is also applicable to the formation of r-butyldimethylsilyl derivatives the silyl ether of cyclohexanol was prepared in 95% yield from allyl-r-butyl-dimethylsilane. Iodine, bromine, trimethylsilyl bromide, and trimethylsilyl iodide have also been used as catalysts. Nafion-H has been shown to be an effective catalyst. ... 

The paper warns that isolated examples of the 1,2,3,4-thiatriazoles are explosive. It starts from the chloro-compound and proceeds thence to allyl and propargyl ethers. The latter, especially, have an additional source of explosive instability [1]. Aminothiatriazoles are reported to explode on melting [2]. 1,2,3,4-thiatriazole-5-thio derivatives are the actual structure of the, generally explosive, azidodithioformic , or azidodithiocarbonic compounds. It seems probable that the 5-oxy compounds are also hazardous, if isolable. There is no immediate reason to suppose the less known 1,2,3,5 thiatriazole system would be much more stable. 

A mild procedure for the appendage of MOM groups to acid-sensitive substrates is illustrated by the protection of the allylic alcohol in Avermectin derivative 259.1 using [(methoxymethyl)thio]-2-pyridine (259 2) sitver(I) Inflate and sodium acetate in THF at room temperature [Scheme 4.259],479 Primary secondary and tertiary alcohols and phenols are methoxymethylated in good yield though phenols are slower to react. Reagent 259.2 (bp 66 °C/0.088 kPa) is easily prepared in 75% yield by the reaction of pyridine-2-thiol with dimethoxy-methane activated by trifluoroborane etherate. 

The substrate-induced diastereoselectivity can be understood in terms of nonbonded steric interactions in the two likely diastereomeric transition states allylic strain between the thio-phenyl or vinyl group (depending on the geometry) and the allylic ether is apparent in only one transition state. 

The use of diphenylcyanomethylphosphine oxide is effective for the synthesis of ( )-a,3-unsaturated nitriles. ° Phosphine oxides can bis used to synthesize a variety of functionalized alkenes, including vinyl ethers (215 equation 51), ° vinyl sulfides (217 equation 52), ° allylic amines (219) and amides (equation 53), " ketene acetals (221 equation 54) and ketene thioketals (223 equation In the examples of a-thio substitution, the alkenes are formed directly. 

Properties M.w. 184.31 sp.gr. 0.993-0.997 b.p. 95-97 C (13 mm Hg) ref. index 1.579 Toxicology TSCA listed Uses Reducing agent for prep, of silyl-substituted alkylidene complexes of tantalum, in ionic reduction of enones to sat. ketones, in reductive cyclization of unsat. ketones, for esters in presence of zinc hydride catalyst, for o-halo ketones in presence of Mo(0), reduction of thio esters to ethers, esters to alcohols with Rh catalysis, in assym. reduction of methyl ketones, reductive cleaving of allyl acetates Manuf./Distrib. ABCR http //www.abcr.de, Alfa Aesar http //www.aifa.com-. Digital Spec. Chems. http //www.digHaichem.com, Fluorochem USA... 

Lewis acid, In(0CF3S02)3, catalysed allylic C—H oxidation of aryl cycloalkenes by l-(propyl thio)pyrrolidine-2,5-dione in the presence of CH2CI2 and various nucleophiles (ROH, RCO2H, RSO2NH2) resulted in the formation of allylic ethers, esters, and sulfonamides in 52-83% yields electron-rich substrates were the most reactive. Other aryl cycloalkenes such as 1-naphthyl, l-(3-thiophenyl)-cyclohexene, 1-phenylcycloheptene, and 1-phenylcyclopentene were suitable substrates. Mechanistic studies showed that the sulfenamide played an important role in converting the allyl sulfide intermediate into the products. ... 

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