Acyl sulfene

Several optically active S-(2-methylbutyl) alkanethioates (25) ° and the naturally occurring thiocar-boxylic esters (26) and (27) were synAesized from the corresponding acid chlorides and thiols, as well as S-phenyl arenecarbothioates and thiocinnamates, which are applicable for the preparation of radio-labeled CoA derivatives (14 equation 17), and the acyl sulfenates (28) occurring in the cultural media of Pseudomonas species (equation 18). ... 

Vinyl and Acyl Sulfines, Vinyl and Acyl Sulfenes... 

VINYL AND ACYL SULFINES, VINYL AND ACYL SULFENES... 

The 4-oxa-l-thia-l,3-butadienes, the acyl sulfines 25 and acyl sulfenes 26, which have been shown to be capable of 4ir participation in selected Diels-Alder reactions, have been summarized in the preceding section. It... 

Acyl sulfenes, like all sulfenes, prefer to participate as 2it components of [2 + 2] or [4 + 2] cycloadditions (Chapter 5). Nonetheless, a range of [4 + 2] cycloaddition reactions of acyl sulfenes have been described46,47 (Scheme 8-XII), including their 4n- participation in dimerization reactions46-48 and reactions with imines,49 carbodiimides,50 ketenimines,51 1-azirines,52 vinyl ethers,53 and ketenes.47 The reactions often provide mixtures of [4 + 2] and [2 + 2] cycloadducts, and the observed course of the reaction usually depends on the reaction conditions. Consequently, many of the observed [4 + 2] cycloadditions of acyl sulfenes proceed by a stepwise, polar addition-cyclization reaction. 

S-Acoxysulfides Acyl sulfenates 20 Monothiolcarbonic acid esters Monothiocarbonate esters 40 Thiolcarbonic acid esters 20 Monothioorthocarboxylic -Monothioorthoformic — Sulfenes... 

Removal of photo>sensitive protective groups 2,4-Dmitrophenylsulfenyl as O-protective group Protection of carboxyl groups as acyl sulfenates... 

On the basis of these findings, the reaction of acyl imines with methanesulfony 1 chloride-triethylamine is not expected to proceed via a sulfene intermediate as previously proposed [99]. Again, a carbanion intermediate accounts nicely for the experimental facts. The electrophihcity of the hetero-l,3-diene is exdemely high, therefore the carbanion, formed on reaction of triethylamme with methanesulfonyl chloride, should undergo nucleophilic attack at C-4 of the hetero-1,3-diene faster than sulfene formabon by chloride elimination. 

The aromatic sulfonyl chlorides which have no a-hydrogen and thus cannot form sulfenes give acylic sulfones. Thus 1-piperidinopropene on reaction with benzene sulfonyl chloride (9J) gave 2-benzenesulfonyl-l-piperidinopropene (153). Similarly the enamine (28) reacts with p-toluene-sulfonyl chloride to give the 2-p-toluenesulfonylcyclohexanone (154) on hydrolysis (/OS). 

This is illustrated by the reaction of enamine, 113 with sulfene to produce adduct 114 in an 80 % yield (146). The product 114 was also observed in an 18% yield from the reaction of diazomethane, sulfur dioxide, and enamine 113 (153). It was demonstrated that this cyclization reaction must involve sulfene adding to the enamine directly and not acylation of the enamine by... 

Acyl isothiocyanates (RCON=C=S) and sulfenes (RCH=S02) react with thiatriazolines to give C=S adducts following path (b) <78JOC495i>. 

Benitez LV, Allison WS (1974) The inactivation of the acyl phosphatase activity catalyzed by the sulfenic acid form of glyceraldehyde 3-phosphate dehydrogenase by dimedone and olefins. J Biol Chem 249 6234-6243... 

The second concealed ElcB elimination is in the elimination of HC1 from MsCl, which we showed you on p. 486 of this chapter. You can now see the similarity with the acyl chloride mechanism above. ElcB to give a sulfene... 

Unerwartet verhalt sich das cis-fixierte Acyl-aldo-enamin 112 (n = 6) gegeniiber Keten. An Stelle der 1.4-Cycloaddition tritt offenbar eine 1.2-Addition zu 141 ein, da 142 als Endprodukt gefaBt wird 77>. Sulfen... 

Chapter 9, Section 1), azodicarboxylates and related acyl and aroyl azo compounds (37, 2,3-diaza-l-oxabutadiene, Chapter 9, Section 5), acy-lsulfines (38) and -sulfenes (39,4-oxa-l-thiabutadiene, Chapter 8, Section 5), yV-sulfinylurethanes (40), and N-sulfonylamides and -urethanes (41, 2-aza-4-oxa-l-thiabutadiene, Chapter 9, Section 3). Chapters 8 and 9 detail the investigations on each of the systems indicated and should be consulted for citations and full discussions of their 4ir participation in Diels-Alder reactions. 

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