One‐Step Synthesis of Arylacetaldehydes from Aryl Aldehydes or Diaryl Ketones via One‐Carbon Extension by Using the System of DMSO/KOH/Zinc

A one‐step protocol is described for the synthesis of arylacetaldehydes from aryl aldehydes or diaryl ketones by using the system of DMSO/KOH/zinc. In this transformation, DMSO provides a methine fragment that converts the −CHO structure in aryl aldehydes or the −CO− structure in diaryl ketones to the −CH2CHO structure in arylacetaldehydes via a one‐carbon extension. This protocol could also be used to synthesize arylacetaldehyde acetals from aryl aldehydes or diaryl ketones when zinc was replaced by diols. In this protocol, 25 examples of arylacetaldehydes and 26 examples of arylacetaldehyde acetals have been synthesized from aryl aldehydes or diaryl ketones. Based on control experiments and the literature, a plausible reaction mechanism is proposed in our work.