Reinhoudt

Sohierbaum K D, Weiss T, Thoden van Velzen E U, Engbersen J F J, Reinhoudt D N and Gdpel W 1994 Moieouiar reoognition by self-assembled monolayers of oavitand reoeptors Sc/e/ ce 265 1413-5... 

Possible conformations of the calix[4]arene systems. (Figure adapted from Fischer S, P D J Groothenuis, roenen, PV P van Hoorn, F C j M van Geggel, D N Reinhoudt and M Karplus 1995. Pathways for mational Interconversion of Calix[4]arenes. Journal of the American Chemical Society 117 1611-1620.)... 

The addition of various alkali and alkaline earth cations to the cyclooligomerization of ethylene oxide by Dale and Daasvatn also provides strong presumptive evidence for the template effect. Recently, Reinhoudt, de Jong and Tomassen utilized several metal fluorides to effect crown formations . The reaction rates were found to be in the order Cs > Rb > > Na LE. Such an order would be expected on the basis of binding... 

Reinhoudt, Gray, Smit and Veenstra prepared a number of monomer and dimer crowns based on a variety of substituted xylylene units. They first conducted the reaction of 1,2-dibromomethylbenzene and a polyethylene glycol with sodium hydride or potassium Z-butoxide in toluene solution. Mixtures of the 1 1 and 2 2 (monomer and dimer) products were isolated and some polymer was formed . The reaction was conducted at temperatures from 30—60° and appeared to be complete in a maximum of one hour. The authors noted that the highest yield of 1 1 cyclic product was obtained with disodium tetraethylene glycolate instead of dipotassium hexaethylene gly-colate (see also Chap. 2) . Chloromethylation of 1,3-benzodioxole followed by reaction with disodium tetraethylene glycolate afforded the macrocycle (29% yield) illustrated in Eq. (3.20). 

Recently, Gray, Reinhoudt and coworkers have prepared a number of furan-con-taining crowns by similar methods ". It is worthwhile noting that these workers prepared considerably larger macrocycles than those prepared by Timko and Cram and the complexation profile for these was obviously different. 

Reinhoudt, de Jong and Tomassen have explored the use of metallic fluorides as bases in the Williamson ether synthesis of crowns. They found that the efficacy order for the metal cations they examined was Cs" > Rb > > Na Li . This order was... 

---