Practical Gram‐Scale Synthesis of Highly Valuable α ‐Arylcycloalkenes From Cyclic Ketones

ABSTRACT

An efficient one‐pot method for the synthesis of α ‐arylcycloalkenes from cyclic ketones and aryl Grignard reagents has been developed. Concentrated hydrochloric acid is added directly to the crude Grignard addition mixture at room temperature, which quenches the excess organomagnesium reagent and affords the α ‐arylcycloalkene without isolation of intermediates. The method accommodates several electronically diverse aryl Grignard reagents and various cyclic ketones, including seven‐ and eight‐membered cyclic ketones, as well as heteroatom‐containing and fused‐ring substrates, providing the desired products in moderate to excellent yields. The reaction can also be performed on gram scales.