Synthesis of Arrays Using Low Molecular Weight MPEG-assisted Mitsunobu Reaction

Triphenylphosphine tagged with a short poly-(ethyleneglycol)-ω-monomethyl ether chain (light MPEG, 10−16 ethylenoxy units, (M)TPP-G2) and an MPEG-tagged version of diethyl azodicarboxylate ((M)DEAD) have been used to prepare a 20 member library of esters, ethers, and sulfonamides, with cLogP's in the range of 1.4−5.7 on a 0.1 mmol scale. Removal of MPEG-tagged side products was achieved by MPEG-assisted solid-phase extraction (MSPE) on prepacked silica columns to give the products in good yield and high purity.