Current Organic Chemistry - Volume 10, Issue 16, 2006

The recent developments of a new chemistry of sulfur dioxide in which this substance adds to 1,3-dienes, acting as a dienophile, are reviewed. Experimental data and theoretical results are analyzed and discussed in order to elucidate the mechanisms through which hetero-Diels-Alder and cheletropic cycloaddition reactions proceed. Discussions about the concerted vs. multi-step nature of the mechanism, the regio- and ste Read More

Although biocatalysts still only account for a relatively small fraction of the total catalyst market, an increasing number of companies are beginning to supplement their range of metal and chemical catalysts with biocatalysts. Consequently, researchers have been trying to take advantage of new technical developments in order to make biocatalysis a viable alternative to traditional synthetic options. Particularly, application of biolo Read More

Ladderanes are hydrocarbons consisting of two or more fused cyclobutane rings. These molecules and their derivatives are of fundamental interest to physical organic chemists due to their strain and electronic properties. Recently, the astonishing discovery that some bacterial lipids contain ladderane substructures has revitalized interest in this class of molecules. This review describes the synthesis, reactivity, applications, an Read More

Cyclic peptides are a special bioactive group of compounds with interesting pharmacological and biochemical properties. Different natural sources are mentioned in this paper, but interest is focused on those cyclopeptides isolated from higher plants and higher fungi. Cyclopeptides occur in higher plant species, which belong to the following families: Annonaceae, Araliaceae, Asteraceae, Caryophyllaceae, Euphorbiaceae, Fab Read More

Isohexenylnaphthazarins (IHN), commonly known as Alkannins and Shikonins (A/S), are lipophilic red pigments. They are found in the outer surface of the roots of at least a hundred and fifty species that belong to the genera Alkanna, Lithospermum, Echium, Onosma, Anchusa and Cynoglossum of the Boraginaceae family. The chiral pairs A/S are potent pharmaceutical substances with a well-established and wide spectrum of wo Read More