Linkers for Carboxyl Functions

Most of the linkers employed for attachment of carboxylic acids have originated from peptide chemistry. These linkers are modified hydroxy, amino or trityl units. Thus, after cleavage from fhe linker, fhe final products contain either a carboxyl or a carboxamide function. Depending on fhe type of linker, cleavage usually proceeds with the TFA concentration varying from 1 % to undiluted ( neat ) TFA. As TFA is volatile, evaporation of fhe solution applied for the release yields fhe product wtifhout impurities. These linkers are described in great detail in the peptide chemistry literature, and most are available commercially. 

Some polymer supports may be purchased wifh the linkers already attached to them. The most prominent linkers of fhis type are outlined in Table 1, togefher with fhe pertinent key references concerning fheir application in combinatorial synfhesis. 

Two silyl-based linkers are also worthy of mention. Both linkers are cleaved by [1- 

Its utility has been demonstrated in the solid-phase synthesis of a number of 

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