Chapter 15 - An Efficient, Multigram Synthesis of Dietary cis- and trans-Octadecenoic (18:1) Fatty Acids

Abstract

The U.S. Food and Drug Administration (FDA) defines trans-fatty acids (TFAs) as fatty acids containing one or more no conjugated double bonds in trans-configuration. In recent years, the Food and Agricultural Organization/World Health Organization (FAO/WHO, 2002. Food and Agriculture Organization of the United Nations/WHO Technical Report Series 916, Geneva) and the American Heart Association (Lichtenstein et al., 2006. Circulation, 114, 82–96) have recommended that the trans-fat content in human diet be less than 1% of total fat consumed for energy. The professional health organizations have noticed that the negative effects of industrially produced TFAs and some government agencies have taken actions to reduce the TFAs contents in processed food. In 2003 Denmark became the first country to set an upper limit on the percentage of TFAs content in foods and prohibiting the sale of foods containing more than 2% industrially produced trans, as percent of total fats (Stender and Dyerber, 2003. A report from the Danish Nutrition Council, fourth ed., Publication No. 34). In 2005 Canada became the first country to regulate the mandatory labeling of trans-fats on prepackaged foods [Health Canada, 2003. Regulations Amending the Food and Drug Regulations (Nutrition Labeling, Nutrient Content Claims and Health Claims), Department of Health, Canada Gazette, Part 11]. Subsequently, the United States introduced mandatory declaration of trans-fats in foods [Food and Drug Administration, 2006. FDA Acts to provide better information to consumers on trans fats 2.005. <www.Health.gov/dietaryguidelines/dga2005/document/> (accessed 17.03.06)]. These actions aimed at reducing the trans-fat content in foods have prompted a renewed interest to improve our understanding of individual TFAs, present in our daily diet. Pure TFAs are currently not available in large quantities and their study is therefore limited. It is necessary to develop reliable methods for large-scale production of individual isomers in high purity. This chapter focuses on efficient synthetic methods of individual cis- and trans-octadecenoic (18:1) fatty acids.