On the Formation of β-Hydroxy-dihydropyrroles from Metal-Catalysed Cyclisations of γ-Ynyl-β-hydroxy-α-amino Esters

David W. Knight; Christopher M. Sharland

doi:10.1055/s-2003-43369

LETTER

On the Formation of β-Hydroxy-dihydropyrroles from Metal-Catalysed Cyclisations of γ-Ynyl-β-hydroxy-α-amino Esters

David W. Knight*, Christopher M. Sharland
Cardiff School of Chemistry, Cardiff University, P.O. Box 912, Cardiff, CF10 3TB, UK
e-Mail: knightdw@cardiff.ac.uk;

Abstract

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Abstract

Copper(I), palladium(II) and mercury(II) salts in hot Et₂O-pyridine mixtures can all induce 5-endo-dig cyclisations of the anti-γ-ynyl-β-hydroxy-α-amino esters 7 to give good yields of the hydroxy-dihydropyrroles 9 and subsequently the related pyrroles 8, following elimination; of the salts tested, copper(I) acetate proved to be the reagent of choice.

Key words

β-hydroxy-dihydropyrroles - γ-ynyl-β-hydroxy-α-amino esters - metal-catalysed cyclisations

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References

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11

All products reported herein have been fully characterized by the usual spectroscopic and analytical data and, where possible, by comparisons with known compounds. [3] [6]

12 For a review of electrophile-driven 5-endo cyclisation methods, see: Knight DW. Prog. Heterocycl. Chem. 2002, 14: 19