Phenylacetylene macrocycles

Keywords Annulenes, Carbon-rich compounds. Macrocycles, Phenylacetylenes, Phenyldia-cetylenes. 

Haley MM, Pak JJ, Brand SC (1999) Macrocyclic Oligo(phenylacetylenes) and Oligo(phenyldia-cetylenes). 201 81-129... 

Over the last decade, the chemistry of the carbon-carbon triple bond has experienced a vigorous resurgence [1]. Whereas construction of alkyne-con-taining systems had previously been a laborious process, the advent of new synthetic methodology based on organotransition metal complexes has revolutionized the field [2]. Specifically, palladium-catalyzed cross-coupling reactions between alkyne sp-carbon atoms and sp -carbon atoms of arenes and alkenes have allowed for rapid assembly of relatively complex structures [3]. In particular, the preparation of alkyne-rich macrocycles, the subject of this report, has benefited enormously from these recent advances. For the purpose of this review, we Emit the discussion to cychc systems which contain benzene and acetylene moieties only, henceforth referred to as phenylacetylene and phenyldiacetylene macrocycles (PAMs and PDMs, respectively). Not only have a wide... 

Cyclization of substituted phenylacetylene sequences afforded functionalized macrocycles that were amenable to subsequent manipulation. For example, transesterification of 42 with octanol in the presence of 18-crown-6 ether and potassium carbonate gave the corresponding ester in 85% yield (Scheme 13). The ester functionalities could be reduced by DIBALH to give the hydroxymethyl-substituted macrocycle (43) in 61 % yield. The low yield of this particular transformation is attributed to mechanical losses during purification, due to the highly polar nature of the product. Macrocycle 43 could then be treated with alkyl bromides to give a group of benzyl ether derivatized PAMs. 

By using monomers with different substituents, multiple functionalities could be introduced into the phenylacetylene oligomer at any desired position along the sequence backbone, resulting in macrocycles with a wide variety of symmetries (e.g. 47-53). In principle, this versatile synthetic method should allow construction of PAMs in which anyparticular group couldbe placed at any particular site. Judicious choice of the type and placement of functionalities has... 

Haley MM, (1999) Top Curr Chem Macrocyclic oligo(phenylacetylenes) and... 

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