Dual iron- and organophotocatalyzed hydroformylation, hydroacylation and hydrocarboxylation of Michael-acceptors utilizing 1,3,5-trioxanes as C1-Synthone

A protocol based on photocatalytic cycles of both iron(III)chloride and 9,10-dicyanoanthracene (DCA) is developed for the masked hydroformylation, hydroacylation, and hydrocarboxylation of Michael-Acceptors utilizing readily available 1,3,5-trioxanes. Initiated by the LMCT of [FeCl4]– to generate chlorine radicals that promote hydrogen atom transfer (HAT) from the trioxanes, 9,10-dicyanoanthracene is used as co-photocatalyst to accelerate the formation of the desired products by facilitating the reoxidation of iron(II) to iron(III). The methodology is robust, allowing the generation of aldehydes, ketones, and carboxylic acids either by altering the trioxane and deprotection strategy or by subsequent photocatalyzed conversion of the initially obtained aldehydes.