Revisiting the Reduction of Di‐ tert ‐butyl Ketone with Alkali Metals

The reduction of di‐ tert ‐butyl ketone ( 1 ) with alkali metals has been revisited. A novel product, 2,5,5‐tri‐ tert ‐butyl‐3‐methyl‐4,5‐dihydrofuran ( 4 ), was isolated from the product mixture in very low yield. The formation of 4 requires the elimination of a methyl radical from the radical anion of 1 as key step. An alternative reaction mechanism, which involves the formation of the dianion of 1 , was ruled out on the basis of the results of DFT calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)