Insight into acid-mediated asymmetric spirocyclization in the presence of a chiral diol.

Asymmetric spirocyclization based on intramolecular conjugate addition using a combination of a Lewis acid and an optically active cyclohexane-1,2-diol has been studied in connection with 1) the effect of substituents on the cyclohexane-1,2-diol and 2) the effect of substituents on the substrate. This reaction was found to be both thermodynamically and kinetically controlled under restricted conditions.