Preparation of Sixteen 3‐Hydroxy‐4‐ and 7‐Hydroxy‐1‐hydrindanones and 3‐Hydroxy‐4‐ and 8‐Hydroxy‐1‐hydroazulenones

Abstract

Abstract3‐Hydroxyoctahydro‐4H‐inden‐4‐ones and 7‐hydroxyoctahydro‐1H‐inden‐1‐ones (1, 2 and 3, 4, respectively), as well as the homologous 3‐hydroxyoctahydro‐4(1H)‐azulenones (5, 6) and 8‐hydroxyoctahydro‐1(2H)‐azulenones (7, 8), were prepared diastereoselectively either from the precursor α,β‐enones 9, 10, 11, and 12 or by an isoxazoline method. Unmasking of the isoxazolines 13i, 14i, and 14j with O3 proved a more stereoselective process than hydrogenolysis. In many cases epimerization with 100 % completeness was observed on passing the epimerizable diastereomers once through a column filled with silica gel, the trans‐fused hydrindanones thus in most cases furnishing the cis‐fused epimers and the cis‐fused hydroazulenones the trans forms. These results have been corroborated by AM1 theoretical computations, which indicate that the cis‐fused epimers in these hydrindanone systems are more stable than the trans‐fused variants, whereas the reverse was calculated for the hydroazulenone homologues. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)