title: On the acidity and reactivity of highly effective chiral Brønsted acid catalysts: establishment of an acidity scale.
abstract: Stronger acid, higher speed: The pKa  values of a range of binol-derived Brønsted acids of three different types were measured and found to correlate directly with the catalytic properties of the acids: higher rate constants kI were observed for more acidic Brønsted acid catalysts (see plot; binol=1,1'-bi-2-naphthol).
authors.affiliation: Institute of Chemistry, University of Tartu, 14a Ravila Street, 50411 Tartu (Estonia).
authors.forename: Karl
authors.initials: K
authors.lastname: Kaupmees
authors.forename: Nikita
authors.initials: N
authors.lastname: Tolstoluzhsky
authors.forename: Sadiya
authors.initials: S
authors.lastname: Raja
authors.forename: Magnus
authors.initials: M
authors.lastname: Rueping
authors.forename: Ivo
authors.initials: I
authors.lastname: Leito
keywords: N-triflylphosphoramides; Nazarov cyclization; acidity; organocatalysis; phosphoric acids