An efficient synthesis of α,β-unsaturated aldehydes by a four-carbon unit extension of Grignard reagents

Copper-catalyzed addition of organomagnesium halides to 2-(2,2-diethoxyethyl)oxirane ( 1 ) affords aldol acetals 2 which upon acid treatment undergo hydrolysis and dehydration to give α,β-unsaturated aldehydes 7 with high yields.