This critical review focuses on the origins and preparation of bio-based surfactants, defined here as non-soap, amphiphilic molecules in which the carbon atoms are derived from annually renewable feedstocks. Environmental concerns and market pressures have led to greater relevance of these chemicals in commercial applications in recent years and extensive research has gone into exploring new classes of surfactants. Highlighted here are examples of bio-based surfactants that are produced on an industrial scale and/or are based on abundant starting materials. The trend of increasing use of renewable resources as starting materials for surfactants is introduced, followed by extensive discussion of the major classes of bio-derived hydrophobes and hydrophiles. Also discussed is the status of research and development with regard to biosynthetically produced surfactants. Finally, concluding remarks address the potential for new surfactant molecular structures as a result of ongoing development in the chemistry of biorefineries, i.e., that the transformation of lignocellulose into fuels is likely to support the manufacturing of new bio-based coproducts (238 references).
Carbohydrate-based surfactants have long been of interest due to their desirable performance properties and their potential to be derived from renewable feedstocks. Although most carbohydrate based surfactants utilize an O-glycosidic linkage, recent advances in carbohydrate C-C bond formation allows for the facile synthesis of new classes of carbohydrate-based surfactants on a C-glycosidic linkage. Herein is described an approach that can generate a wide variety of C-glycoside surfactants in moderate to very good yield by treating the nonulose C-glycoside intermediate first described by Lubineau et al. with pyrrolidine in the presence of an alkyl aldehyde. Depending on the stoichiometry and reaction conditions, this chemistry will result in either a linear enone C-glycoside, or a cyclohexenone C-glycoside, both of which demonstrate interesting surfactant properties. Further, the linear enone series can be photochemically modified or reacted with other alkyl aldehydes to generate additional analogs.This journal is
Naturally occurring arylnaphthalene lactone lignans have demonstrated a variety of valuable medicinal chemistry properties and have therefore been of continued interest to drug discovery research. Our group has demonstrated a silver-catalyzed one-pot synthesis of the arylnaphthalene lactone core using carbon dioxide, phenylpropargyl chloride, and phenylacetylene. This new approach has been employed in the synthesis of six arylnaphthalene lactone natural products: retrochinensin (1), justicidin B (2), retrojusticidin B (3), chinensin (4), justicidin E (5), and taiwanin C (6). Additionally, an arylnaphthalene lactone regioisomer was isolated (9), which we refer to as isoretrojusticidin B.
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