- Total synthesis of (+)-batzelladine A and (-)-batzelladine D via [4 + 2]-annulation of vinyl carbodiimides with N-alkyl imines
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A diastereoselective [4 + 2]-annulation of vinyl carbodiimides with chiral N-alkyl imines has been developed to access the stereochemically rich polycyclic guanidine cores of the batzelladine alkaloids. Application of this strategy, together with additional key steps such as long-range directed hydrogenation and diastereoselective intramolecular iodo-amination, led to highly convergent total syntheses of (-)-batzelladine D and (+)-batzelladine A with excellent stereocontrol.
- Arnold, Michael A.,Day, Kenneth A.,Duron, Sergio G.,Gin, David Y.
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p. 13255 - 13260
(2008/03/11)
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- Diastereoselective [4+2] annulation of vinyl carbodiimides with N-alkyl imines. Asymmetric synthetic access to the batzelladine alkaloids
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A diastereoselective [4+2] annulation of vinyl carbodiimides with chiral N-alkyl imines has been developed to access the stereochemically rich tricyclic core of the batzelladine alkaloids. Its application to the asymmetric synthesis of batzelladine D perm
- Arnold, Michael A.,Duron, Sergio G.,Gin, David Y.
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p. 6924 - 6925
(2007/10/03)
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- Synthesis and Reactivity of Electron-Poor 2-Azadienes. Cycloaddition Reactions with Alkenes and Enamines
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Electron deficient 2-azadienes derived from β-amino acids 3 are obtained by aza-Wittig reaction of N-vinylic phosphazenes 4 with carbonyl compounds.Inverse electron demand Diels-Alder reaction of azadienes 3 with trans-cyclooctene 7 and cis,trans-cyclooctadiene 8 leads to the formation of trans-cycloalkanotetrahydropyridines 10.Heterodienes 3 also react with enamines 13, 14, and 18 affording pyridine derivatives 16, 17, and 20 in a regioselective fashion.Norbornadiene 11, a less strained olefin than cycloalkenes 7 and 8, requires the presence of lithium perchlorate as catalyst in a nonaqueous solvent like ether, to give cycloadducts 12.
- Palacios, Francisco,Heredia, Itziar Perez de,Rubiales, Gloria
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p. 2384 - 2390
(2007/10/02)
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- Preparation and Reactivity of Electron-poor 2-Azadienes. Diels-Alder Reaction with Trans-Cyclooctene.
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Di-, tri-, and tetra-substituted 2-azadienes 3 with electron-withdrawing groups have been obtained by Aza-Wittig reaction of N-vinylic phosphazenes with carbonyl compounds.The Diels-Alder reaction of 3 with trans-cyclooctene has also been explored. Key Words: Azadienes, Phosphazenes, Aza-Wittig reaction, Diels-Alder reaction
- Palacios, Francisco,Heredia, Itziar Perez de,Rubiales, Gloria
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p. 4377 - 4380
(2007/10/02)
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- Reactions of Iodine(I) Azide with αβ-Unsaturated Carbonyl Compounds
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The addition of iodine(I) azide to some αβ-unsaturated esters and ketones has been examined.Addition to the esters under nitrogen gives products consistent with a radical pathway.Preliminary kinetic results indicate that addition of iodine(I) azide to αβ-unsaturated ketones in the presence of air involves a slow electrophilic attack.Reaction with methyl trans-cinnamate under these conditions does not go to completion.
- Cambie, Richard C.,Jurlina, Jeffrey L.,Rutledge, Peter S.,Swedlund, Bernard E.,Woodgate, Paul D.
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p. 327 - 334
(2007/10/02)
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