text: The addition of a 1,3-dithiane alters reactivity by inverting this value through the formation of a masked acyl anion.
full_question: The addition of a 1,3-dithiane alters reactivity by inverting this value through the formation of a masked acyl anion. The synthetic technique that inverts this property was pioneered by Dieter Seebach and E.J. Corey, and is called umpolung. When 1,3-dicarbonyl compounds are in environments low in this quantity, they prefer to exist in a cyclic enol form. The rate of an SN1 reaction shows a relative increase when this quality of the solvent is enhanced. This property is absent in tetrachloromethane, but is present in chloromethane. This property determines the migration rate of a sample when using chromatography. Bonds will have this property when the two atoms have a large difference in electronegativity. For 10 points, name this property found in molecules with an uneven distribution of charge.
first_sentence: The addition of a 1,3-dithiane alters reactivity by inverting this value through the formation of a masked acyl anion.