Telechelic polyisobutylenes (PIB) find widespread use in fuel and lubricating oils, sealants, and adhesives. Recently, telechelic PIBs have been synthesized via a process known as end quenching, in which living PIB cations are reacted with a quenching molecule at full IB conversion thereby introducing a functional group to the end of the chain. One method of end quenching that has not been investigated is quenching via the Ritter reaction, which utilizes a nitrile in the presence of a carbocation to form an amide via a nitrilium ion intermediate. Herein, we report our attempts at PIB chain end functionalization via the Ritter reaction under end quenching conditions and classical Ritter conditions using various PIB substrates, nitriles and acid catalysts. When performed on small molecule analogs of PIB, the Ritter reaction proceeded smoothly and the expected acrylamide was isolated in high yields. When polymeric PIB substrates were used, the Ritter-type addition of the nitrile was not observed, and isolated products indicated loss of chain end fidelity via carbocationic rearrangement or no reaction, presumably due to the immiscibility of the nitrile and the PIB substrate. Finally, we report the derivitization of squalene, an oligomeric analog of polyisoprene, via the Ritter reaction to form a new family of small molecule crosslinkers.

End quenching of polyisobutylene substrates via the Ritter reaction

254th National Meeting (2017)

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