A<unk>  or tandem<unk>  or domino<unk>  is a consecutive series of intramolecular organic<unk> s which often proceed via highly reactive intermediates. It allows the organic synthesis of complex multinuclear molecules from a single acyclic precursor. The substrate contains many functional groups that take part in chemical transformations one at the time. Often a functional group is generated in situ from the previous chemical transformation. The definition includes the prerequisite intramolecular in order to distinguish this<unk>  type from a multi-component<unk> . In this sense it differs from the definition of a biochemical<unk> . The main advantages of a<unk>  in organic synthesis are that the<unk>  is often fast due to its intramolecular nature, the<unk>  is also clean, displays high atom economy and does not involve workup and isolation of many intermediates.
A<unk>  is sometimes called a living<unk>  because it shares some characteristics with a living polymerization. In<unk> s one can identify an initiation site, a relay moiety and a termination moiety.  Examples of<unk> s are numerous (e.g. the Aldol-Tishchenko<unk>  and especially so in alkyne chemistry (the Banert<unk>  to name just one) or polyolefin polycycloisomerizations. Other alkyne coupling<unk> s are classified based on common features such as type of compound synthesised, for instance the spiro mode<unk>  :
or the linear-fused mode<unk>   ,through application of the intramolecular Heck<unk> :
or the zipper mode<unk>  .
Other<unk> s are included in Diels-Alder<unk> s, oxirane ring-opening<unk> s   , and Pauson–Khand<unk> s .
An example of an oxirane<unk>  is given by the synthesis of certain polyether ladder polymers :
This type of ladder compounds are found in marine lifeforms such as red tide.  The tri-epoxide is prepared from a triene through asymmetric Shi epoxidation and oxone as primary oxidizing agent. The hydroxyl group in the tri-epoxide is activated as a nucleophile by the presence of the base caesium carbonate The bulky trimethylsilyl groups make such that the polyether is formed with the correct stereochemistry and they are removed in situ by caesium fluoride.
Cascade reaction
Cholesterol emboli syndrome
Edwards syndrome
Postperfusion syndrome
Coronary vasospasm
Hyperdynamic circulation
Paradoxical embolism
No-reflow phenomenon