Introduction of Allyl and Prenyl Side‐Chains into Aromatic Systems by Suzuki Cross‐Coupling Reactions

Abstract

Abstract This paper reports some studies aiming at the developement of a general protocol useful for the synthesis of allyl‐ and prenylaromatic compounds. The first part deals with the preparation of boron reagents like arylboronic acids and their pinacol esters as well as of pinacol allyl‐ and prenylboronates. The second part of the paper is devoted to the use of these boron reagents in Suzuki–Miyaura cross‐coupling reactions leading to allylation and prenylation of aromatic compounds. Of the six methods studied, the most promising results were obtained by using the Pd 2 (dba) 3 ‐catalyzed reactions of arylboronic acids with allyl and prenyl bromides, that lead to the products of cross coupling in high yields (average 87%), and the reactions of aryl trifluoroborates with allyl and prenyl bromides catalyzed by Pd(OAc) 2 that lead to the products of coupling in all cases in high yields (average 82%).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)