Facile Synthesis of 2-Hydroxy-6-methylbenzaldehyde, an Alarm and Sex Pheromone Component of Astigmatid Mites

Abstract

2-Hydroxy-6-methylbenzaldehyde (5) is a component of astigmatid mites, functioning as the alarm and sex pheromones, and the establishment of its convenient synthesis is prerequisite and of vital importance to develop applications of these pheromones for practical use. The target compound (5) was effectively synthesized from m-cresol (1) by the following four steps in a 44% overall yield: protection of the hydroxyl group by a tetrahydropyranyl group, blocking the active site (6-position of 1) by a trimethylsilyl group via lithiation and subsequent silylation, formylation via lithiation and successive quenching by dimethylformamide, and deprotection by a trifluoroacetic acid treatment.