Solvolytic enolization of scytalone

[GRAPHICS] The major conformation of scytalone has an envelope shape with C3 forming t he flap and the C3 hydroxyl in the equatorial position as determined by qua ntum mechanical calculations and corroborated by NMR. The C2 axial pro-R is slower to exchange with solvent than the equatorial pro-S hydrogen. Modeli ng the transition state for enolate formation points to a deprotonation thr ough the flipped envelope conformation in which the C3-hydroxyl and the C2 pro-S hydrogen are axial.