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Synthesis 2002(15): 2271-2279
DOI: 10.1055/s-2002-34950
PAPER
© Georg Thieme Verlag Stuttgart · New York

Palladium(0)-Catalyzed Allylation of 2,2′-Dihydroxybiphenyl by 1-Ethenylcyclopropyl Sulfonates: Preparation of 2,2′-Bis(cyclopropylideneethoxy) biphenyls

Giovanna Delogu*a, Jacques Salaün*b, Cristina de Candiaa,b, Davide Fabbria,b, Pier Paolo Pirasc, Jean Ollivierb
a Istituto di Chimica Biomolecolare, Sez: Sassari, CNR, Traversa La Crucca 3, reg. Baldinca, Li Punti, 07040 Sassari, Italy
b Laboratoire des Carbocycles, UMR 8615, Institut de Chimie Moléculaire d’Orsay, Bât. 420, Université de Paris-Sud, 91405 Orsay, France­
Fax: +33(1)69156278; e-Mail: jasalaun@icmo.u-psud.fr;
c Dipartimento di Scienze Chimiche, Cittadella Universitaria Monserrato, 9042 Monserrato, Italy
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Publication History

Received 22 June 2002
Publication Date:
21 October 2002 (online)

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Abstract

Dipotassium salts of 2,2′-dihydroxybiphenyl derivatives underwent palladium(0) catalyzed regioselective allylation by sulfonic esters (mesylates, tosylates) of 1-ethenylcyclopropanol to produce, in good yields, 2,2′-bis(cyclopropylideneethoxy)biphenyls, which are of biological interest. Whilst the tetrapotassium salt of 2,2′,6,6′-tetrahydroxybiphenyl, formed the triadduct 2,2′-tris(cyclopropylideneethoxy)hydroxybiphenyl as its main product. An unexpected palladium-induced rearrangement of the monoadducts 2-(2-cyclopropylideneethoxy)-2′-hydroxybiphenyl derivatives into the 2-[2-(1-ethenylcyclopropyloxy)]-2′-hydroxybiphenyl derivatives occurred; while the minor diastereomer of the monoadduct 2-[(2-cyclopropylidene-1-trimethylsilyl)ethoxy]-6,6-dimethoxy-2′-hydroxybiphenyl upon standing in CDCl3, underwent Claisen re­arrangement into the 2,2′-dihydroxy-6,6′-dimethoxy-3-(2-tri­methylsilylethenyl)cyclopropylbiphenyl.

Key words

palladium(0) - 1-ethenylcyclopropyl sulfonates - biphenyls - allylation - rearrangements