A general and convenient method for the synthesis of 2,4-dinitrobenzyl ketones. Almost unlimited access to 2-substituted 6-nitroindoles from 2,4-dinitrotoluene and aldehydes

2,4-Dinitrotoluene reacts in the presence of catalytic amounts of DBU with aldehydes to form the corresponding alcohols in good yields (usually above 65%). The obtained alcohols can be readily oxidized to 2,4-dinitrobenzyl ketones, which were used for the synthesis of 6-nitroindoles with various substituents in the 2-position. Starting from non-racemic aldehydes, non-racemic 2-substituted 6-nitroindoles were obtained. Starting from 2,4-dinitrotoluene and aldehydes, 2-substituted 6-nitroindoles with alkyl, cycloalkyl, aryl and heteroaryl (thienyl, furyl, pyridyl) substituents in the 2-position of the indole ring were synthesized. This methodology can be used for synthesis of indoles with non-racemic substituents.