Current Organic Synthesis - Volume 7, Issue 1, 2010

This review highlights the development of new receptors based on enantiopure trans-cyclohexane-1,2-diamine, a chiral building block presenting unique structural and conformational properties. Different architectures sharing this structural motif, which were prepared following several synthetic approaches, have been summarized from the recent literature.

This review summarizes the different synthetic strategies based on chemical templation for the construction of threaded and interlocked molecules (rotaxanes, pseudorotaxanes and catenanes). The chemical templates or intermolecular interactions used to bring together in an organised fashion the different component parts of the threaded or interlocked structures can be divided into: anionic and cationic templates, hydrogen bonding interactions, π-stacking and charge-transfer interactions and hydrophobic interactions. Examples of the most common structures displaying these interactions will be discussed.

Interest in organoselenium chemistry has been increasing for the last 25 years. This paper reviews the use of sodium selenide and its hydrogenated form (NaHSe, H2Se) for the preparation of a wide variety of selenium-containing heterocycles.

The progress that has been made in organic synthesis via the reactions of nitrogen derivatives of carbonyl compounds with phenyliodoso diacetate is presented. The synthesis of various aliphatic, alicyclic and heterocyclic compounds is discussed. Emphasis is given in a synthetically useful new transformation of hydroxyl into a carbonyl group that leads to high yield synthesis of 1,2-diacylsubstituted compounds.

Under catalysis with an appropriate Lewis acid, the intermolecular Diels-Alder cycloaddition and intramolecular polyene cyclization of the α-activated cross conjugated cycloalkenone systems, possessing particularly increased dienophilicity/electrophilicity in the cross conjugated double bond, proceeded constantly with a high degree of stereochemical control, leading to a variety of synthetically useful molecules, which may serve as advanced intermediates towards many structurally challenging natural products, especially cisclerodane diterpenoids. Mechanistically, an additional conjugated double bond incorporated into the cycloalkenone core of the titled systems might contribute synergistically to the classical secondary orbital effects, thus significantly enhancing the endo-to-ketone addition. In addition, a tandem multiple sig-bond migration process, an enzymatic pathway prevalent in nature, was proposed to rationalize the formation of structurally unusual polyene-cyclization products occurring under standard chemical conditions.