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Letters in Organic Chemistry

Editor-in-Chief

ISSN (Print): 1570-1786
ISSN (Online): 1875-6255

Tandem Intramolecular Carbolithiation-Lithium / Zinc Transmetallation: A Synthetically Versatile Combination

Author(s): M. Yus and R. Ortiz

Volume 1, Issue 4, 2004

Page: [365 - 368] Pages: 4

DOI: 10.2174/1570178043400659

Price: $65

Abstract

The carbolithiation of 1-lithiohex-5-ene (2) gives cyclopentylmethyllithium (3), which after treatment with zinc dibromide yields a solution of the corresponding organozinc reagent (5). The palladium(II)-catalysed acylation of this compound with several acyl chlorides yields the expected ketones (6). By a copper(I)-promoted reaction of compound (5) with different allylic or propargylic chlorides or bromides, a very clean SN2 reaction takes place giving the expected olefins (7) or allenes (8), respectively. The palladium(II)-catalysed arylation of intermediate (5) with different aryl bromides or iodides affords the corresponding substituted arenes (9). Finally, the copper(I)-promoted conjugate addition of compound (5) to some α,β-unsaturated ketones gives the expected ketones (10), without any contamination of the corresponding 1,2-adducts.

Keywords: intramolecular carbolithiation, lithium-zinc transmetallation, electrophilic substitution, arene-catalysed lithiation


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