Chloromethylated polystyrene, cross-linking mechanism

The synthesis of cu-amino-substituted 18-crown-6 and [2.2.2]cryptand readily bonded with chloromethylated polystyrene cross-linked by different amounts of DVB, is described [86]. Such bonded polyesters are used as interfacial transfer catalysts promoted by anions. As in the case of analogous soluble systems, the catalytic activity of cryptands is higher than that of crown ethers and quaternary onium salts. Because of their high chemical stability, such catalysts can be regenerated without chemical decomposition. However, the impairment of mechanical properties caused by comminution of the polymer matrix remains to be solved. 

Recently chloromethylated polystyrene (CMS), a highly sensitive, high resolution electron resist with excellent dry etching durability, was developed. Very recently reactive intermediates in irradiated polystyrene, which is a starting material of CMS, have been studied and the transient absorption spectra of excimer (2-4), triplet states (2,5), charge-transfer complexes, and radical cations (6) of polystyrene have been measured. The present paper describes the cross-linking mechanism of the high sensitivity CMS resist and compares it to that of polystyrene on the basis of data on reactive intermediates of polystyrene and CMS. 

The polymer-bound catalysts A-C. (Table 31) are prepared by reaction of the corresponding amino alcohols with partially chloromethylated 1 -2% cross-linked polystyrene. In the case of A, the enantioselectivity of the addition of dialkylzincs to aldehydes is higher than with the corresponding monomeric ephedrine derivatives (vide supra). Interesting insights into the mechanism of the alkylation of aldehydes by dialkylzinc reagents can be obtained from the experi-... 

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