The Brønsted acid catalyzed acetalization of aldehydes with alcohols is one of the most common transformations in organic synthesis and yet catalytic asymmetric versions, until today, have been entirely unknown [Eq.(1)].[1] The advent of asymmetric Brønsted acid catalysis has recently enabled the enantioselective generation of chiral N, N-, N, O-, and N, S-acetals, either from imines or directly from aldehydes.[2, 3] The success of these ...
