A Review on Chemical Synthesis of Leaf Alcohol

Abstract: Leaf alcohol is a flavor and fragrance compound and has been shown to possess an intense characteristic grassy-green odor of freshly cut green grass and leaves, which is widely used as an added flavor in fragrances, food flavors and tobacco flavors to provide a fresh grassy note. However, the market has been unable to meet this surge in demand, resulting in a frequent shortage of leaf alcohol. At present, there are two processes used in industrial production: the process for the hydrogenation of 3-hexyn-1-ol and the process for the ring opening reaction of 6-methyl-3,6-dihydro-2H-pyran. The reason for the shortage is that there are certain difficulties and shortcomings in the current methods of synthesizing leaf alcohol. The disadvantages of the process for the hydrogenation of 3-hexyn-1-ol are the production security and dependability, the prime cost of catalyst and equipment. The disadvantages of the process for the ring opening reaction of 6-methyl-3,6-dihydro-2H-pyran are the product quality, production dependability, and the prime cost of the equipment. To solve this contradiction between supply and demand, many research groups are investigating chemical synthetic methods that could be applied in industrial production easily and economically. Since the discovery of leaf alcohol, much has happened in the synthesis of leaf alcohol. Many developments became market realities, so after all these years, it seemed appropriate to sum up the current trends in the synthesis of leaf alcohol. In this review, we bring a collection of various synthetic approaches leading to leaf alcohol.