Inverted Stereoselectivity in Grignard Additions to Chiral Aldehydes by Use of Polyethers.
نویسندگان
چکیده
منابع مشابه
Evidence that Additions of Grignard Reagents to Aliphatic Aldehydes Do Not Involve Single-Electron-Transfer Processes.
Addition of allylmagnesium reagents to an aliphatic aldehyde bearing a radical clock gave only addition products and no evidence of ring-opened products that would suggest single-electron-transfer reactions. The analogous Barbier reaction also did not provide evidence for a single-electron-transfer mechanism in the addition step. Other Grignard reagents (methyl-, vinyl-, t-Bu-, and triphenylmet...
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The degree of reagent and substrate control in the reaction of chiral sulfur ylides with chiral aldehydes has been investigated. Specifically, the reactions of the two enantiomers of the chiral benzyl sulfonium salt 1 with glyceraldehyde acetonide were studied in detail. Of the two new stereogenic centers created, it was found that the C1 stereochemistry was largely controlled by the reagent, w...
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متن کاملHow to prepare a chiral Grignard reagent: a theoretical proposal.
It is shown that two competitive pathways (T2 vs T4) exist for Grignard reagent formation. While the nonradical pathway T2 leads to retention of the configuration, the radical pathway T4 gives racemization. Our calculations suggest the way that T2 can be enhanced, which should be of significance to prompt new synthesis approaches for the preparation of chiral Grignard reagents.
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ژورنال
عنوان ژورنال: Acta Chemica Scandinavica
سال: 1986
ISSN: 0904-213X
DOI: 10.3891/acta.chem.scand.40b-0440