Iterative Exponential Growth through Manipulation of Sulfide Oxidation States

Discovering methods to produce polymers of precisely defined length and sequence has been an age-old vexation for synthetic chemists. Classical polymerization techniques such as step growth and chain growth tend to produce inexact polymer sequences with broad ranges of molecular weights. Other techniques, such as solid state peptide synthesis, that allow construction of sequence defined oligomers, grow at a sluggish, linear rate. This research aims to explore a contemporary technique, iterative exponential growth (IEG), which utilizes a convergent/divergent strategy to grow oligomers of exact sequence and size in an exponential fashion. Specifically, we aim to use nucleophilic aromatic substitutions as a coupling strategy to drive the IEG. With our strategy, methyl sulfide substituents will be used to mask leaving groups, which can be accessed through oxidation. Six distinct evolutions of our approach have been studied, in pursuit of discovery of an ideal system which should couple in high yields.