Synthesis of α-hydroxy and α-oxospiranes through ruthenium(II)-catalyzed ring-closing metathesis

Abstract

Efficient methodology for the construction of functionalized spiranes using Ru(II)-catalyzed ring-closing metathesis reactions is described. The substrates were appropriately substituted five-, six- and seven-membered cycloalkanes which were spiroannulated by five-, six- and seven-membered rings, respectively. The relative stereochemistry of selected substituted spiranes has been determined by single crystal X-ray analyses. The X-ray structures formed the basis for NMR correlations of the relative stereochemistry in the groups of compounds prepared. Relative rates in oxidation reactions could also be used for stereochemical correlations.