Octols, synthesis

Scheme 3.6 General synthesis of octols and cavitands from resorcinol.

The problem of the solubility of the final carcerand was obviated by the use of phenylpropionaldehyde or hexanal in the initial synthesis step (coupling with 264). Thus the respective analogs of octol 265 were manufactured. Further transformations performed in the same way as is shown in Scheme 4.82 gave modified carcerands 267 and 268 containing phenylethyl or -butyl residues instead of methyl in the parent comound 263. Both 267 and 268 were isolated as carceplexes (carcerand plus guest, G) in yields of 20-30%. Seven individual carceplexes were prepared and fully characterized as a result of the described modification of the starting materials. 

Hogbeig AG (1980) Cyclooligomeric phenol-aldehyde condensation products. Stereoselective synthesis and DNMR study of two l,8,15,22-tetraphenyl[14]metacyclophan-3,5,10,12,17,19,24,26-octols. J Am Chem Soc 102 6046-6050... 

In contrast to the parent calix[4]arenes, selective functionalization of the resorcinol-based calix[4]arenes [ 18] has hardly been studied. Partly functionalized cavi-tands have only been isolated as side products in the synthesis of tetrafunctionalized cavitands [19, 20]. Although such dissymmetric cavitands have been used in the synthesis of chiral cavitands [21] and hemicarcerands [20] with promising applications [22], their synthesis was never studied in detail. While our work was in progress [23], Sorrell and Richards showed that cavitands can be selectively functionalized at the upper rim by means of a Claisen rearrangement [24]. In this paper we describe the synthesis of partly bridged octols [25] together with a novel route to functionalize these cavitands selectively in a proximal way. 

First, we optimized the synthesis of tri-bridged diol 3 by variation of the reaction conditions, temperature (and the reaction time), solvent, and amount of CHaBrCl. These reactions were carried out with octols with different side chains (Ri). The results are summarized in Table IV. 

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