But-2-ene-l-thiol

IUPAC name methanethiol butane-1-thiol but-2-ene-l-thiol 2-mercaptoethanol... 

The odor of thiols is their strongest characteristic. Skunk scent is composed mainly of 3-methylbutane-l-thiol and but-2-ene-l-thiol, with small amounts of other thiols. Ethanethiol is added to natural gas (odorless methane) to give it the characteristic gassy odor for detecting leaks. 

The most striking characteristic of thiols is their appalling odor. Skunk scent, for instance, is caused primarily by the simple thiols 3-methylbutane-l-thiol and but-2-ene-l-thiol. Volatile thiols such as ethanethiol are also added to natural gas and liquefied propane to serve as an easily detectable warning in case of leaks. 

But-2-ene-l-thiol is one component of skunk spray. How would you synthesize this substance from methyl but-2-enoate ... 

Significant aliphatic sulfur compounds are methional, 3-methyl-but-2-ene-1-thiol, 3-mercapto-3-methylbutan-l-ol (8-124), its ester 3-mercapto-3-methylbutyl formate, methanethiol and dimethyltrisulfide. 3-Mercapto-3-methyl-l-ol also occurs in passion fruit and blackcurrant, and as a putative cat pheromone in cat urine, where it is formed as a degradation product of amino acid L-felinine (see Section 2.2.1.2.2). Of more than 70 known pyrazines, the most important compounds in roasted coffee are isopropylpyrazine, 2-isobutyl-3-methoxypyrazine, 2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, 2,6-dimethyl-3-vinylpyrazine and 2-ethyl-6-methyl-3-vinylpyrazine. Pyridine and its alkyl derivatives and bicyclic pyridines have a negative impact on the quality of coffee aroma. Important aromatic... 

Amines, thiols, eOH (p. 226), etc., will also add to the 0-carbon atom of 0-unsaturated carbonyl compounds and esters, but the most important reactions of C=C—C=0 systems are in Michael reactions with carbanions reactions in which carbon-carbon bonds are formed. A good example is the synthesis of l,l-dimethylcyclohexan-3,5-dione (dimedone, 100) starting from 2-methylpent-2-ene-4-one (mesityl oxide, 101) and the carbanion 0CH(CO2Et)2 ... 

A useful route toward heteronines is an application of 1,3-dielectrophiles when they react with O- and S-nucleophiles. The chiral (R)-l,l -bi-2-naphthol 152 was reacted with 3-chloro-2-(chloromethyl)prop-l-ene to afford dioxonine 153 (Scheme 28, Section 14.10.6.1) <1998JA5943, 1997TA2921>. A novel procedure for the preparation of cyclic polythioethers by the reaction of dithioiminium salt with 1,3-dihalopropane using phase-transfer catalyst has been reported (Equation 28) <2003PS1295>. This approach avoided the use of thiols, which are not only hard to handle, but also prone to oxidation. 

Addition of thiols to 2-methoxycarbonylbicyclo[2,2,l]hept-5-enes is reported. Addition of acetic acid to 2-ethylidenebicyclo[2,2,l]heptane at 40 °C gives (595). Norbornene has been converted into its exo-thiiran derivative by addition of ArSSCl, treatment with Na2S, and distillation. Addition of 2,4-dinitrophenylsulphenyl chloride, ArSCl, to norbornene in acetic acid gives mainly (596) but in the presence of LiC104 mainly (597). A further set of examples confirms that the ratio of substitution to addition in the reaction of polychloronorbornadienes is very sensitive to small... 

The key components of fresh grapefruit juices with a typical grapefruit odour are both isomers of p-mentha-l-en-8-thiol (8-188). The (- -)-(Ji)-enantiomer is present in minute concentrations (less than 1 (xg/kg), but has a very low odour threshold concentration. The (-)-(S)-p-mentha-l-ene-8-thiolhas aweak and non-specific smell. Of the other sulfur compounds, 4-mercapto-4-methylpentan-2-one (8-125) is significant, and also occurs in blackcurrants, some hop cultivars, aromatic wines and basil. A relatively high content of sesquiterpenoids is also typical. The smell and bitter taste of grapefruits arise from (-l-)-nootkatone and (-1-)-8,9-didehydronootkatone. Important odour-active compounds are numerous cyclic ethers, which are likewise found in other essential oils. For example, the essential oil contains about 13% of hnalool oxides that arise from linalool via 5,6-epoxide, and another important epoxide is ( )-4,5-epoxydec-2-enal. The fresh odour of juices is mainly influenced by aliphatic aldehydes, such as acetaldehyde. 

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