Catalytic aldol-type reaction of aldehydes with ethyl diazoacetate using quarternary ammonium hydroxide as the base

The direct aldol-type condensation of aldehydes with ethyl diazoacetate (EDA) promoted by an organic base and non-metallic catalyst such as tetrabutylammonium hydroxide (TBAOH) gave β-hydroxy-α-diazocarbonyl compounds with moderate to excellent yields. Furthermore, the reactivity and scope of various phase-transfer catalysts as well as electronically divergent aldehydes are discussed.