Hydrophobic‐Substrate‐Selective Dehydrative Condensations at the Emulsion Interface under Conditions where Competitive Reactions Proceed in the Bulk Aqueous Phase

The synthetic utility is demonstrated of substrate‐selective dehydrative condensations at emulsion interfaces using amphiphilic 1,3,5‐triazine‐based dehydrative condensing reagents. To this end, it was investigated whether reaction selectivity between carboxylic acids is pronounced even at relatively high concentrations of reactants and reagents where a background reaction occurs in the bulk aqueous phase. Amide formation was selective for longer‐chain carboxylic acids when the difference in alkyl chain length was 4–5 carbons. The ratio of product amides could be predicted using the log P value of the carboxylic acids. These results were applied to a one‐pot parallel dehydrative condensation where two different reaction fields, inside and outside of the aggregates, were used in the presence of two carboxylic acids and two amines to selectively give two out of four possible amides. Hydrophobic‐substrate‐selective dehydrative condensations at emulsion interfaces using amphiphilic 1,3,5‐triazine‐based dehydrative condensing reagents were carried out at concentrations of reactants (100 mM max.) and reagents high enough for background reactions in water to potentially compete. The product ratio of amides can be predicted using the log P value of the substrates.