Some acyclic pentaalkoxyphosphoranes

Chang, Lydia L.; Denney, Donald B.; Denney, Dorothy Z.; Kazior, Richard J.

doi:10.1021/ja00449a044

Cited by 43 publications

(11 citation statements)

References 14 publications

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“…Based on the Livinghouse conditions,' a solution of methyl benzenesulfenate (0.126 g; 0.875 mmol, prepared from diphenyldisulfide following the methods of Mueller and Butler (14) and Denny and co-workers (15), in MeN0, (1 1.9 mL) was cooled to -30°C under argon. Previously prepared BF3/MeN02 (1.34 mL of 1.24 M) was added and after stirring 2.5 min the diene 5a (0.207 g; 0.817 mmol) was added in MeNO, (2 mL) and stirring was continued for 2 h at -30°C.…”

Section: Cyclization Of Diene 5amentioning

confidence: 99%

Approach to the synthesis of candelabrone and synthesis of 3,7-diketo- 12-hydroxyabieta-8,11,13-triene

Burnell¹,

Caron²

1992

Can. J. Chem.

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992). An approach to the synthesis of aromatic diterpenes was tested for its generality. Phenylacetonitriles with increasing substitution on the aromatic ring were prepared and alkylated with geranyl bromide and the resulting dienes subjected to cationic cyclization. The less-substituted examples afforded tricyclic products of the required stereochemistry while the more highly substituted compounds cyclized with reduced yields or not at all. One of the intermediates was used to synthesize nimosone (3,7-diketo-12-methoxyabieta-8,11,13-trine) a natural diterpene isolated originally from Chamaecyparis forrnoserlsis and recently from Azadirachta indica.ROBERT H. BURNELL et STEPHANE CARON. Can. J. Chem. 70, 1446 ( 1992). Une sene de phCnylacCtonitriles substituks par une chaine gCranyle et un nombre croissant de groupements mkthoxyles a Cte soumise B des conditions de cyclisation cationique pour determiner la generalit6 de la rCaction. Seulement les substrats les moins encombrCs ont rCagis efficacement donnant les produits tricycliques de la stCrCochimie requise et un de ces derniers a semi comme intermediaire clC pour la synthese de la nimosone, une dicetone diterpenique isolCe de Chat7zaecyparis fortnosensis et plus rkcemment de Azadirachtc~ indica.In recent years more examples of aromatic diterpenes with oxygen functions in the A ring have appeared in the literature. Hypagenins A , D , and E (I), candelabrone (2) and several coleons (3) fall in this category and the neem tree, Azadirachta indica, is a rich source of these new compounds (4). Few syntheses are reported for these products since many of the schemes that start with simpler naturally occuring chiral terpenes, such as podocarpic and dehydroabietic acids (5), do not lend themselves readily to the introduction of functions into the A ring past the quaternary centres at C 4 and C10. A more total approach could be advantageous but, unlike those derived from chiral precursers, the final products from most sequences would be racemic.After first probing the application of radical cyclizations of the type described by Snider et al. (6) it was decided to test the generality of the cationic equivalent as championed by Livinghouse and co-workers (7). Ultimately we hope to apply the scheme to the synthesis of candelabrone 1 but the first objective was the simpler 3,7-diketo-12-hydroxyabieta-8,11,13-triene 2a originally isolated from Chamaecyparis formosensis (8) and more recently from Azadirachita iizdica when it was given the name nimosone (4a).This synthetic approach involves the cyclization of nonconjugated dienes such as 5 a in which half the molecule '~u t h o r to whom correspondence may be addressed.comes from the naturally derived geranyl bromide 3 and the other 10 skeletal carbon atoms are provided by substituted phenylacetonitriles, such as 4. Specifically the latter has been prepared from o-isopropylanisole 6a in an overall yield of close to 65%. Bromination of 6a by potassium bromide and m-CPBA in the presence of 18-crown-6 afforded 84% of the bromo der...

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Section: Cyclization Of Diene 5amentioning

confidence: 99%

Approach to the synthesis of candelabrone and synthesis of 3,7-diketo- 12-hydroxyabieta-8,11,13-triene

Burnell¹,

Caron²

1992

Can. J. Chem.

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“…Thus, chlorination of thiol 1 with sulfuryl chloride furnished 4. Sulfenyl chloride 4 was condensed with (À)-menthol at 0°C in the presence of Et 3 N as previously described for the preparation of alkyl benzenesulfenates 19 to provide the desired sulfenate 5, although, in only 20% yield.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric oxidation of sulfenates to sulfinates as a new route to optically active ortho-phosphorylated phenyl sulfoxides

Grach¹,

Abrunhosa²,

Gulea³

et al. 2005

Tetrahedron: Asymmetry

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“…16 Ethyl benzenesulfenate was prepared as described earlier. 22 Sulfenylhalogenation of alkenes and dienes with ethyl benzene sulfenate in the presence of trimethylsilyl halides or thionyl halides (general procedure). A solution of trimethylsilyl halide or thionyl halide in anhydrous CHCl 3 (or CH 2 Cl 2 ) was slowly added drop wise under dry argon at room temperature to a vigorously stirred solution of an approximately equimolar mixture of an alkene (or a diene) and ethyl benzenesulfenate in the corresponding solvent.…”

Section: Methodsmentioning

confidence: 99%

A new method for the activation of ethyl benzenesulfenate in electrophilic addition reactions

et al. 2008

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Reactions of unsaturated compounds with the PhSOEt-SOHal 2 and PhSOEt-Me 3 SiHal systems (Hal = Cl or Br) were proposed as a new route to haloalkyl phenyl sulfides. With acyclic and mono and bicyclic alkenes and dienes as examples, the regio and stereoselectivity of the reactions were studied.Electrophilic addition of such sulfenic acid derivatives as sulfenyl chlorides is a well studied and convenient route to sulfur containing compounds. 1 Sulfenylbromination, 2,3 iodination, 4 and fluorination 5 have been studied less thoroughly because of the low stability of the starting sulfe nyl halides. Addition of stable sulfenic acid derivatives (sulfenamides) to multiple bonds occurs only in the pre sence of strong protic 3 or Lewis acids. 2,4-8 It should be noted that halosulfenylation, 2-6 aminosulfenylation, 7 or sulfamatosulfenylation 8 are possible when an appropriate activator is employed. Only a few studies have been devot ed to the sulfenylation of unsaturated compounds with sulfenic acid esters (sulfenates). 9-12 Earlier, we have reported on new methods for halo sulfenylation of olefins through their reactions with ethyl benzenesulfenate in the presence of phosphorus oxoha lides 13 and trimethylsilyl halides. 14 In the present work, we studied the possibility of sulfenylating alkenes and dienes with ethyl benzenesulfenate in the presence of trimethylsi lyl halides and thionyl halides.These reactions are very easy to implement: a solution of a coreagent (SOHal 2 or Me 3 SiHal; Hal = Cl or Br) is slowly added to a solution of an alkene and a sulfenate in chloroform (or dichloromethane) and the mixture is stirred at room temperature until the reaction is completed (15-20 min). Then the mixture is passed through a col umn with silica gel and the eluate is concentrated. In most cases, the resulting product requires no additional purifi cation. The structures of the products were determined by 1 H and 13 C NMR spectroscopy. The compositions of the novel compounds were confirmed by GC MS or elemen tal analysis data.The reactions of ethyl benzenesulfenate with cyclohex ene and norbornene (Scheme 1) in the presence of SOHal 2 (Hal = Cl or Br), as in the case of Me 3 SiHal, proceed stereospecifically to give trans β haloalkyl phenyl sulfides in nearly quantitative yields (Table 1). Scheme 1Hal = Cl (2a, 4a), Br (2b, 4b)

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Some acyclic pentaalkoxyphosphoranes

Cited by 43 publications

References 14 publications

Approach to the synthesis of candelabrone and synthesis of 3,7-diketo- 12-hydroxyabieta-8,11,13-triene

Approach to the synthesis of candelabrone and synthesis of 3,7-diketo- 12-hydroxyabieta-8,11,13-triene

Asymmetric oxidation of sulfenates to sulfinates as a new route to optically active ortho-phosphorylated phenyl sulfoxides

A new method for the activation of ethyl benzenesulfenate in electrophilic addition reactions

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