Catalyzed Williamson etherification

The major difference between our reaction conditions and the conventional phase transfer catalyzed Williamson etherification (22) is the use of stoichiometric amounts of phase transfer catalyst versus the nucleophilic chain ends in the former case. Under these... 

In conclusion, phase transfer catalyzed Williamson etherification and Wittig vinylation provided convenient methods for the synthesis of polyaromatics with terminal or pendant styrene-type vinyl groups. Both these polyaromatics appear to be a very promising class of thermally reactive oligomers which can be used to tailor the physical properties of the thermally obtained networks. Research is in progress in order to further elucidate the thermal polymerization mechanism and to exploit the thermodynamic reversibility of this curing reaction. 

Initially, polyethers based chromophore 1 were synthesized to explore the chemistry of the dye and to develop discotic liquid crystalline materials. These materials were prepared by phase transfer catalyzed Williamson etherification (Scheme 1). The first prepared polyether was based on 1 and had a spacer length of four methylene units (n=4, x=0). This demonstrated the chemistry, but the material possessed limited solubility in common organic solvents. Consequently, longer spacers (n=10, x=0) were incorporated to prepare soluble homopolymers of 1. The iH-NMR spectrum confirmed the structure but the polymer displayed a glass transition temperature of 100 °C. Furthermore, the absence of a melting point and a WAXD crystalline structure indicated the materials were amorphous. 

Allylation conditions are similar to those used for benzylation to a certain extent. Williamson s etherification using allyl bromides and NaH smoothly produces the allyl ethers [85], NaH can be replaced with BaO when base-sensitive moieties are present in the molecule [86, 87], The use of allyl imidates or TMSOTf-catalyzed Et3SiH-reductive allylation of a TMS ether using allyl aldehydes also provides the... 

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