Inside Back Cover: On the Catalysis of the Cycloisomerization of 1,6‐Dienes with Tin(IV) Salts: The Important Role of a Water Molecule (ChemCatChem 2/2014)

Abstract

Water gets the cat out of the tin The cover picture shows a key transition state involved in the cyclisation of 1,6-dienes catalysed by a tin catalyst. In the computations and experiments presented in their Full Paper on p. 500 ff., P. Nava et al. explain how a water molecule is necessary for reaction completion and catalyst regeneration. It is shown that the tin cation does not directly participate in the reaction but sits aside on an ester lone pair of the diene. A water molecule, strongly acidic owing to its coordination to the metal, is positioned perfectly over the substrate and transfers protons at the right places along the cyclisation process (orange dots). The catalysis and its diastereoselectivity are determined completely by this coordinated water molecule.