The gem-dialkyl effect in electron transfer reactions: rapid synthesis of seven-membered rings through an electrochemical annulation.

An electrochemical furan annulation strategy has been developed for the synthesis of seven-membered rings. Key to the success of the annulation is the placement of a gem-dialkyl group in the tether. Voltammetric studies indicate that this effect lowers the oxidation potential by approximately 110 mV.