Synthesis and Diels-Alder reactions of homochiral 2-sulfinylmaleates with cyclopentadiene

Alonso, Inés; Cid, M. B.; Carretero, Juan C.; Ruano, José Luis Garcı́a; Hoyos, Miguel A.

doi:10.1016/s0957-4166(00)80020-8

Cited by 24 publications

(4 citation statements)

References 29 publications

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“…The best catalyst was lithium perchlorate, the use of which as a suspension in dichloromethane gave only the endo isomers 15A R and 16A R in 70% yield in the ratio 96:4. This was the first illustration that lithium perchlorate suspended in dichloromethane-catalyzed DA reactions and that it did so highly stereoselectively. Reetz and Fox have shown that Mukaiyama aldol reactions and conjugate additions were more efficiently catalyzed in this way than by 5 M lithium perchlorate in diethyl ether, conditions that were previously advocated for the dramatic acceleration of DA reactions …”

Section: Resultsmentioning

confidence: 83%

Synthesis and Asymmetric Diels−Alder Reactions of Enantiopure 3-(Alkylsulfinyl)-1-methoxy-1,3-butadienes

et al. 1997

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Simple syntheses of enantiopure (E)- and (Z)-3-(alkylsulfinyl)-1-methoxy-1,3-butadienes 2and 3 were provided by the addition of (1S)-isoborneol-10-sulfenic and (S)-phenyl-2-hydroxyethanesulfenic acids 8 to (E)- and (Z)-1-methoxybut-1-en-3-ynes (9) and (10). These additions proceeded with asymmetric induction, the extent of which depended upon the nature of the chiral hydroxyalkyl group. Cycloadditions of methyl acrylate to the enantiopure dienes proceeded with complete regioselectivity and very high stereoselectivity when catalyzed by lithium perchlorate or zinc chloride in dichloromethane. The chirality at sulfur controlled the diastereofacial selectivity in these Diels-Alder cycloadditions.

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Section: Resultsmentioning

confidence: 83%

Synthesis and Asymmetric Diels−Alder Reactions of Enantiopure 3-(Alkylsulfinyl)-1-methoxy-1,3-butadienes

et al. 1997

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“…The identification of the other fractions could not be achieved through analysis of NMR spectra; the hydrogens α to the carboxylic ester and to the sulfinate functionality were very similar in the 1 H NMR spectra, allowing no means to initiate assignments of the observed resonances. To gain more information about the structure of the individual cycloadducts, we subjected them to halocyclization conditions typically employed to induce ester attack of the remote alkene . The hope was that at the very least, the configuration of the carboxylic ester group in the various cycloadducts could be elucidated.…”

Section: Resultsmentioning

confidence: 99%

Diels−Alder Cycloadditions of Ethyl 2-Carbomethoxyethenesulfinates with Cyclopentadiene. Lewis Acid Enhancement and Adduct Identification with the Assistance of Competitive Stereodifferentiating Iodolactonization and Iodosultinization Reactions

Lear

Schwan

1999

J. Org. Chem.

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Ethyl (Z)-2-carbomethoxyethenesulfinate (1) and ethyl (E)-2-carbomethoxyethenesulfinate (2) were each subjected to cyclopentadiene (ca. 3 equiv) in order to determine their reactivity in Diels-Alder reactions. Thermal reactions proceeded in less than 4 h, while Lewis Acid enhanced reactions were substantially faster and demonstrated greater selectivity. In particular, the BF(3).Et(2)O-mediated cycloaddition of 1 gave syn/endo cycloadduct 3a as a major diastereomer in about 90% yield. The reactions of 2 were less synthetically useful. The structures of the cycloadducts were established through a combination of X-ray crystal structure determinations and through exposure of the compounds to an electrophilic iodine reagent. Each cycloadduct underwent an iodocyclization reaction with either the carboxylic ester or the sulfinate ester participating in the formation of a polycyclic lactone or sultine, respectively. The iodocyclization reactions allowed further elucidation of the cycloadduct structures.

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“…In order to avoid symmetrization, selective monodemethylation and further re-esterification were required as previous steps of desulfinylation (see transformation exo(t)-89 AE in Scheme 46). The synthesis of p-tolylsulfinyl maleates with differentiated carboxylic functions was accomplished to overcome these limitations, and so to improve the scope of the sulfinyl maleates as chiral dienophiles [89,90]. In these papers, the synthesis of the half-esters 93 and 94 as well as the mixed diester 95, and their reactions with cyclopentadiene under different conditions, were reported.…”

Section: Sulfinyl Maleates and Sulfinyl Maleimidesmentioning

confidence: 99%

Asymmetric [4+2] Cycloadditions Mediated by Sulfoxides

Ruano

Plata

1999

Topics in Current Chemistry

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Asymmetric [4+2] cycloadditions involving the use of enantiomerically pure sulfoxides as the main controller of stereoselectivity are reviewed. Diels-Alder reactions with sulfinyldienes and sulfinyldienophiles, 1,3-dipolar reactions with vinylsulfoxides, and hetero-Diels-Alder reactions are the main objectives of this review. The influence of the sulfinyl group on the reactivity, regioselectivity, and especially stereoselectivity of these reactions has been mainly considered in order to understand the synthetic scope and limitations of the sulfinyl group acting as a chiral inductor in these reactions. Apparent deficiencies in proposed stereochemical models have been also highlighted.

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Synthesis and Diels-Alder reactions of homochiral 2-sulfinylmaleates with cyclopentadiene

Cited by 24 publications

References 29 publications

Synthesis and Asymmetric Diels−Alder Reactions of Enantiopure 3-(Alkylsulfinyl)-1-methoxy-1,3-butadienes

Synthesis and Asymmetric Diels−Alder Reactions of Enantiopure 3-(Alkylsulfinyl)-1-methoxy-1,3-butadienes

Diels−Alder Cycloadditions of Ethyl 2-Carbomethoxyethenesulfinates with Cyclopentadiene. Lewis Acid Enhancement and Adduct Identification with the Assistance of Competitive Stereodifferentiating Iodolactonization and Iodosultinization Reactions

Asymmetric [4+2] Cycloadditions Mediated by Sulfoxides

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