Scalable synthesis of enantiomerically pure bicyclo[2.2.2]octadiene ligands.

Stefan Abele, Roman Inauen, Dirk Spielvogel, Christian Moessner

Index: J. Org. Chem. 77(10) , 4765-73, (2012)

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Abstract

An operationally simple and scalable synthesis of enantiomerically pure bicyclo[2.2.2]octadiene (bod*) ligands relying on an organocatalytic one-pot Michael addition-aldol reaction with cheap 2-cyclohexenone and phenylacetaldehyde is presented. The crystalline bicyclic product 4a (6-hydroxy-5-phenylbicyclo[2.2.2]octan-2-one) is transformed into phenylbicyclo[2.2.2]oct-5-en-2-one 2, a versatile starting material for the 2-step synthesis of both symmetrical, such as Hayashi's Ph-bod* ligand, as well as novel unsymmetrical chiral dienes.