Reduction of o-iodophenyl 3-methylbut-2-enyl ether with samarium diiodide generates mixtures of 3-isopropyl-2, 3-dihydrobenzofuran and 3-(2-propenyl)-2, 3-dihydrobenzofuran along with a small amount of dimer. If a source of deuterium is present during the reduction, then the 3-isopropyl product predominates and this product is labeled with one deuterium. However, attempts to quench the putative tertiary organosamarium reagent by adding a ...