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Conjugate Addition of ß-Keto Ester Dianions to Vinyl Sulfones: A New Procedure for Seven-Ring Annulation. Synthesis of a Chiral Cytochalasin C Intermediate via an Intramolecular Diels-Alder Reaction of a Chiral Z Diene

Journal Article


Abstract


  • Conjugate addition reactions of dimethylhydrazone anions and β-keto ester dianions to a chiral sterically hindered vinyl sulfone are reported. Further functionalization of the resulting α-sulfonyl-stabilized anion by alkylation with allyl bromide followed by reductive desulfonylation, ozonolysis, and intramolecular aldol reaction provides an enolized α-carboalkoxy enone, the net result being a new annulation sequence for the synthesis of seven-membered rings. Determination of the relative stereochemistry of conformationally mobile cis- and trans-fused bicyclo[5.4.0] systems by combined Karplus/molecular mechanics calculations is described. Cyclization of a pair (40, 3) of chiral Z dienes via an intramolecular Diels-Alder reaction stereospecifically affords chiral polycyclic adducts (41, 4) that are potential precursors for cytochalasin C. © 1982, American Chemical Society. All rights reserved.

Publication Date


  • 1982

Citation


  • Pyne, S. G., Spellmeyer, D. C., Chen, S., & Fuchs, P. L. (1982). Conjugate Addition of ß-Keto Ester Dianions to Vinyl Sulfones: A New Procedure for Seven-Ring Annulation. Synthesis of a Chiral Cytochalasin C Intermediate via an Intramolecular Diels-Alder Reaction of a Chiral Z Diene. Journal of the American Chemical Society, 104(21), 5728-5740. doi:10.1021/ja00385a030

Scopus Eid


  • 2-s2.0-0344696252

Web Of Science Accession Number


Start Page


  • 5728

End Page


  • 5740

Volume


  • 104

Issue


  • 21

Abstract


  • Conjugate addition reactions of dimethylhydrazone anions and β-keto ester dianions to a chiral sterically hindered vinyl sulfone are reported. Further functionalization of the resulting α-sulfonyl-stabilized anion by alkylation with allyl bromide followed by reductive desulfonylation, ozonolysis, and intramolecular aldol reaction provides an enolized α-carboalkoxy enone, the net result being a new annulation sequence for the synthesis of seven-membered rings. Determination of the relative stereochemistry of conformationally mobile cis- and trans-fused bicyclo[5.4.0] systems by combined Karplus/molecular mechanics calculations is described. Cyclization of a pair (40, 3) of chiral Z dienes via an intramolecular Diels-Alder reaction stereospecifically affords chiral polycyclic adducts (41, 4) that are potential precursors for cytochalasin C. © 1982, American Chemical Society. All rights reserved.

Publication Date


  • 1982

Citation


  • Pyne, S. G., Spellmeyer, D. C., Chen, S., & Fuchs, P. L. (1982). Conjugate Addition of ß-Keto Ester Dianions to Vinyl Sulfones: A New Procedure for Seven-Ring Annulation. Synthesis of a Chiral Cytochalasin C Intermediate via an Intramolecular Diels-Alder Reaction of a Chiral Z Diene. Journal of the American Chemical Society, 104(21), 5728-5740. doi:10.1021/ja00385a030

Scopus Eid


  • 2-s2.0-0344696252

Web Of Science Accession Number


Start Page


  • 5728

End Page


  • 5740

Volume


  • 104

Issue


  • 21