Propargyl Chlorides as Sources for Cobalt Stabilized γ-Carbonyl Cations

Document Type

Article

Publication Date

11-1-1995

Publication Title

Journal of Organic Chemistry

Volume

60

Issue

23

First Page

7496

Last Page

7502

Abstract

Hexacarbonyldicobalt complexes of γ-chloroalkynones and γ-chloroalkynoates (5) weee found to undergo silver-mediated Nicholas condensation reactions with silyl enol ethers or silyl ketene acetals (10) to give 1,6-dicarbonyl complexes 11 in fair to good yields. Substrates 5 with γ-alkyl substitution formed diastereomeric products with enol silanes 10a and 10b. Reactions with propiophenone trimethylsilyl enol ether (10b) gave good levels of syn diastereoselection, whereas reactions with cyclohexanone trimethylsilyl enol ether (10a) weee only slightly diastereoselective, favoring the anti diastereomer. When conducted in acetonitrile, the silver-mediated reaction of 5e gave a radical dimerization product 13, isolated as the syn diastereomer. © 1995, American Chemical Society. All rights reserved.

DOI

10.1021/jo00128a022

ISSN

00223263

E-ISSN

15206904

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