Quantitative Methylation of Lignin Monomers Using Tetrabutylammonium Hydroxide and MeI and Applications in Organic Synthesis

Efficient O-alkylation of phenols and carboxylic acids has essential applications in organic synthesis. A mild alkylation method for phenolic and carboxylic OH groups is developed using alkyl halides as alkylation reagents and tetrabutylammonium hydroxide as a base, and lignin monomers can be fully methylated in quantitative yields. Additionally, phenolic and carboxylic OH groups can be alkylated by different alkyl halides in one pot in different solvent systems.