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The biosynthetic pathways to a number of natural products have been reconstituted in vitro using purified enzymes. Many of these molecules have also been synthesized by organic chemists. Here we compare the strategies used by nature and by chemists to reveal the underlying logic and success of each total synthetic approach for some exemplary molecules with diverse biosynthetic origins.
Morphine, an alkaloid isolated from the opium poppy, has been widely used as an analgesic, and has been a fascinating synthetic target of organic chemists. After the first total synthesis reported in 1952, a number of synthetic studies toward morphine have been reported, and findings obtained in such studies have greatly contributed to the progress of synthetic organic chemistry as well as medicinal...
Recently, hypervalent iodine reagents have been used extensively in organic synthesis. In particular, (diacyloxyiodo)benzenes such as phenyliodine(III) diacetate (PIDA) and phenyliodine(III) bis(trifluoroacetate) (PIFA) have received a great deal of attention due to low toxicity, ready availability, easy handling, and reactivities similar to that of heavy metal reagents and anodic oxidation. A variety...
Total syntheses of the natural products kelsoene and preussin are comprehensively reviewed. Kelsoene is a sesquiterpene with a unique tricyclo[6.2.0.02,6]decane skeleton. It contains six stereogenic centers the selective construction of which has been addressed differently in the five syntheses known to date. Three syntheses employ an intermolecular [2+2]-photocycloaddition reaction as key step. One...
Recent advances in strategies for the synthesis of manzamine-related alkaloids are summarized and discussed. We particularly focus on strategies for the formation of a complex central ring core, especially substituted hydroquinoline, and the formation of medium and large azacycles.
Among nature's ecosystems, the marine environment has been an extremely rich source of structurally complex and biologically active molecules. This review aims to cover the recent developments in the synthesis of marine natural products, also reflecting the trend of their increased use to address biological questions. The examples chosen should be viewed as representative of the different structural...
The isolation, structure and total synthesis of members of four classes of diterpenes has been summarized. Dolabellanes, neodolabellanes, dolastanes and neodolastanes are structurally related bi- or tricyclic diterpenes. Dolabellanes belong to a continuously growing class of diterpenes being isolated from marine and terrestrial sources. The published work on isolation and synthesis since 1998 has...
In the late 1990s, the Caribbean octocoral Pseudopterogorgia elisabethae became the target of extensive chemical investigations leading to the isolation and characterization of a remarkable number of diterpenoid secondary metabolites. Most of these newly discovered compounds are based on so far unprecedented carbon skeletons and often feature unusual structural characteristics. Besides their exciting...
An overview of the application of microwave irradiation in natural product synthesis is presented, focusing on the developments in the last 5–10 years. This contribution covers the literature concerning the total synthesis of natural products and their analogues, the synthesis of alkaloids and the construction of building blocks of interest for natural product synthesis. As microwave irradiation appeared...
Medium-ring ethers, specifically those produced by the marine genus Laurencia, have attracted the attention of many synthetic chemists since 1965, when the isolation of laurencin, the first medium-ring ether from Laurencia, was reported by Irie. These medium oxacycles typically possess one or more halogen groups adjacent to an ethereal oxygen atom and an enyne or a bromoallene side chain. Therefore,...
A review on the total syntheses of bioactive compounds and natural products published in the last decade using phosphonate reagents and phosphonate-based methodologies is presented.
The Pummerer and Pummerer-type reactions of sulfoxides generate sulfonium ion intermediates, to which either internal or external nucleophilic species add to form carbon–carbon and carbon–heteroatom bonds at the α-position of the sulfur functional groups. Lately, various kinds of new reactions initiated by the Pummerer and Pummerer-type reactions have been developed. These reactions have received...
Over the years, Friedel–Crafts (FC) alkylation has become one of the most useful synthetic tools for C—C bond formation involving aromatic compounds. Stoichiometric and, more recently, catalytic procedures have been applied in the total synthesis of a large number of natural products and targeted bioactive compounds. This chapter reviews the authors’ choice of published syntheses involving FC alkylation...
This chapter provides an overview of the Ramberg‐Bäcklund reaction (RBR), with pertinent recent examples, for practitioners of organic chemical synthesis. The focus is on strategies and considerations relevant to the application of the RBR in synthesis. Several preparative methods for sulfones exist for generating RBR precursors. The most popular for complex target synthesis, is to introduce the sulfur...
Consideration of the mechanism of the quasi‐Favorskii rearrangement quickly reveals that there are a number of related reactions, including the benzylic acid rearrangement and the pinacol rearrangement. This chapter focuses on processes that proceed via an anionic tetrahedral intermediate that breaks down via expulsion of some leaving group and concomitant bond migration to generate the product observed...
Among the array of reactions available to alter molecular complexity, pinacol and semipinacol rearrangements have a particularly long history. With a clearer understanding of the factors governing their regio‐ and stereoselectivity, as well as more powerful variants (including asymmetric) that can induce the rearrangement under mild conditions, these rearrangement processes have a number of specific,...
This chapter describes total syntheses of natural products and related compounds in which transition‐metal‐catalyzed processes cleaving C–C bonds are involved. They present unique synthetic strategies that are otherwise difficult to conduct.
The advantages of zinc catalysts, such as their low toxicity, low cost, and environmentally benignity, are encouraging organic chemists to explore their applications in organic synthesis, especially in total synthesis. Numerous applications have been developed over the past few decades. This chapter will summarize the main contributions in this field.
Multicomponent reactions (MCRs) are mostly experimentally simple to perform, often without the need of dry conditions and inert atmosphere. MCRs provide a huge chemical diversity and currently more than 300 different scaffolds have been described in the chemical literature. A strategy to enhance the size and diversity of current MCR chemical space is the concept of combining a MCR and a subsequent...
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