A New Synthesis of Muscone and Exalrone@. The Enamine Approach of Ring-Enlargement Reaction Key reaction in the synthesis of the title compounds is the treatment of the aldehydes 6 and 7 (obtained from 1) with a primary amine, e.g. pentylamine, in EtOH at room temperature. After stirring overnight, the products 8 and 9, respectively, are obtained in good yields. Both are enlarged by three ring members and can be transformed to Exdtoiz@ (12) and (+)-muscone, (13), respectively.