Catalytic Asymmetric Reactions between Alkenes and Aldehydes

This doctoral work describes catalytic asymmetric reactions between alkenes and aldehydes, enabled by the development of chiral Brønsted acids. Valuable and functionalized enantiomerically enriched cyclic compounds were efficiently furnished from inexpensive and commercially available reagents with high degrees of atom economy. In the first part of this thesis, the first highly enantioselective organocatalytic intramolecular carbonyl−ene cyclization of olefinic aldehydes is presented. In the second part, asymmetric cyclizations via oxocarbenium ions are described. One is a general asymmetric catalytic Prins cyclization of aldehydes with homoallylic alcohols, in which the oxocarbenium ion is attacked intramolecularly by a pendent alkene. The other one is an asymmetric oxa-Pictet−Spengler reaction between aldehydes and homobenzyl alcohols, in which the oxocarbenium ion is trapped by an intramolecular arene. The first general asymmetric [4+2]-cycloaddition of simple and unactivated dienes with aldehydes is developed in the last part of this thesis. This methodology is extremely robust and scalable. Valuable enantiomerically enriched dihydropyran compounds could be readily obtained from inexpensive and abundant dienes and aldehydes. New types of confined Brønsted acids were rationally designed and synthesized, including imino-imidodiphosphates (iIDPs), nitrated imidodiphosphates (nIDPs), and imidodiphosphorimidates (IDPis). Beyond the application of these catalysts in various asymmetric reactions between simple alkenes and aldehydes, mechanistic investigations are also disclosed in this doctoral work