70738-46-4Relevant academic research and scientific papers
Isomerisation of Vinyl Sulfones for the Stereoselective Synthesis of Vinyl Azides
Collins, Niall,Connon, Robert,Evans, Paul,Sánchez-Sanz, Goar
, p. 6228 - 6235 (2020)
Reported is the construction, and facile base-mediated conversation of ten differently substituted 3-azido E-vinyl sulfones (γ-azido-α,β-unsaturated sulfones) into their isomeric vinyl azide counterparts. The requisite 3-azido E-vinyl sulfones were prepared from 3-bromo E-vinyl sulfones, which in turn were accessed from allyl sulfones via a bromination-elimination sequence. In relation to this a one-pot azidation-isomerisation sequence was developed which enabled the direct formation of the vinyl azides from the corresponding 3-bromo E-vinyl sulfones. Similarly, a convenient one-pot Horner–Wadsworth–Emmons olefination-isomerisation approach was utilised in order to prepare some of the allylic sulfones used in this study. The vinyl azide forming process typically proceeded with high levels of Z-selectivity, although this was dependent on the vinyl sulfone substitution pattern. Thus, with either no substituent or a methyl group in the γ- or β-position, relative to the sulfone, good, to high levels of Z-selectivity (Z/E = 85:15 to ≥ 95:5) were obtained. However, incorporation of an α-sulfonyl methyl substituent led to an E-selective process (Z/E = 20:80). A non-bonding interaction between the azido group and the α-sulfonyl vinylic proton is proposed, which acts as a conformational control mechanism to help guide the stereochemical outcome.
A base-controlled regioselective synthesis of allyl and vinyl phenyl sulfones
Dana, Dibyendu,Davalos, Anibal R.,Subramaniam, Gopal,Afzal, Nisar,Hersh, William H.,Kumar, Sanjai
, p. 2717 - 2721 (2013/06/26)
A reaction of diethyl phenylsulfonylmethylphosphonate with 2-arylacetaldehydes in the presence of a catalytic excess of sodium hydride (1.1 equiv) yields allyl phenyl sulfones in excellent yield under mild reaction conditions. In contrast, when less than 1 equiv of sodium hydride (0.90 equiv) is used, the corresponding vinyl phenyl sulfones are obtained exclusively. The vinyl phenyl sulfones can be completely converted to allyl phenyl sulfones with only 0.2 equiv of NaH, suggesting that the second hydride involvement in the above transformation is catalytic. The regioselective control observed in these reactions offers a general method for synthesizing novel vinyl and allyl phenyl sulfones in one step from the same starting materials. The regioselectivity and stereoselectivity of this reaction, however, are not maintained when 2-alkylacetaldehydes are reacted with diethyl phenylsulfonylmethylphosphonate under identical reaction conditions. Our results indicate that an extended conjugation of the double bond in allylsulfones formed from the reaction of 2-arylacetaldehydes is required for the observed regio- and stereoselectivity.
Asymmetric synthesis of cycloalkenyl and alkenyloxiranes from allylic sulfoximines and aldehydes and application to solid-phase synthesis
Gais, Hans-Joachim,Babu, Gadamsetti S.,Guenter, Markus,Das, Parthasarathi
, p. 1464 - 1473 (2007/10/03)
An asymmetric synthesis of cycloalkenyl and alkenyloxiranes from allylic sulfoximines and aldehydes is described. Lithiation and titanation of cyclic and acyclic allylic sulfoximines with chlorotris(diethylamino)titanium and subsequent treatment with aldehydes gave, as described previously, enantio-and diastereomerically pure, syn-configured, sulfoximine-substituted homoallylic alcohols. Treatment of the sulfoximine-substituted homoallylic alcohols with chloroethyl chloroformate resulted in a facile substitution of the sulfoximine group by a Cl atom, with formation of the corresponding alkenyl chlorohydrins. In the case of the cycloalkenyl derivatives the substitution proceeded with high diastereoselectivities with retention of configuration, while in the case of the alkenyl derivatives, medium diastereoselectivities with inversion of configuration were observed. While elimination reactions of the cycloalkenyl chlorohydrins gave the corresponding enantio- and diastereomerically pure cis-configured cycloalkenyloxiranes in good overall yields, the alkenyl chlorohydrins afforded mixtures of enantiomerically pure trans and cis isomers in which the trans isomers dominated. The solution-phase synthesis was extended to the solid phase by the synthesis of an enantiomerically pure, polymer-bound allylic sulfoximine and its conversion into an alkenyloxirane. The initial results proved that the concept of the utilization of the sulfoximine group as a traceless chiral linker is feasible and suggest that the solid-phase asymmetric synthesis of cycloalkenyloxiranes by this route should be possible. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Electrochemical oxidation of carboxylic acid anions in the presence of some mono- and di-subsituted olefins
Champagne, Philippe J.,Renaud, Roger N.
, p. 1101 - 1105 (2007/10/02)
The anodic oxidation of the sodium salts of acetic, propionic, and isovaleric acids was performed in the presence of a series of ethylenic compounds bearing electron-withdrawing substituents.The results showed that under certain experimental conditions the electrogenerated radicals added to the ethylenic double bond to give mainly 1,2-dialkylated products.The stereoisomers obtained were separated and whenever possible, identified.Their physical properties are reported.
