Template reaction

In <a href="/facts/Chemistry/SrNqkGVm">chemistry</a>, a template reaction is any of a class of <a href="/facts/Ligand/6etB3qeW">ligand</a>-based reactions that occur between two or more adjacent coordination sites on a metal center. In the absence of the metal ion, the same organic reactants produce different products. The term is mainly used in <a href="/facts/Complex_(chemistry)/1tCyeQUm">coordination chemistry</a>. The template effects emphasizes the pre-organization provided by the coordination sphere, although the coordination modifies the electronic properties (acidity, electrophilicity, etc.) of ligands.
An early example is the dialkylation of a nickel dithiolate:

The corresponding alkylation in the absence of a metal ion would yield polymers. <a href="/facts/Crown_ether/UNfhBQs5">Crown ethers</a> arise from dialkylations that are templated by alkali metals. Other template reactions include the <a href="/facts/Mannich_reaction/4JbDmfHE">Mannich</a> and <a href="/facts/Schiff_base/yg29UMLe">Schiff base</a> condensations. The condensation of <a href="/facts/Formaldehyde/Ck8RLfqk">formaldehyde</a>, ammonia, and <a href="/facts/Tris(ethylenediamine)cobalt(III)/CfN8EvnK">tris(ethylenediamine)cobalt(III)</a> to give a <a href="/facts/Clathrochelate/0pIKtToE">clathrochelate</a> complex is one example.

The phosphorus analogue of an <a href="/facts/Aza_crown/7lRAwG2K">aza crown</a> can be prepared by a template reaction. Where it is not possible to isolate the phosphine itself.

Template reaction open-in-new

Template reaction