Catalytic Asymmetric Reactions between Alkenes and Aldehydes
2017
This doctoral work describes catalytic asymmetric reactions between alkenes and
aldehydes, enabled by the development of chiral Bronsted 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 Bronsted 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.
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