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Organocatalytic Strategies to Stereoselectively Trap Photochemically Generated Hydroxy‐ o ‐quinodimethanes
Author(s) -
Cuadros Sara,
Melchiorre Paolo
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800081
Subject(s) - enantioselective synthesis , chemistry , organocatalysis , cycloaddition , intermolecular force , combinatorial chemistry , catalysis , photochemistry , organic chemistry , computational chemistry , molecule
Light excitation of ortho ‐alkyl aromatic ketones and aldehydes gives access to hydroxy‐ o ‐quinodimethanes. These reactive electron‐rich intermediates are sufficiently long‐lived to productively engage in chemical processes, mainly acting as dienes in [4+2]‐cycloadditions with electron‐poor alkenes. Since the early discovery of this photoenolization mechanism in 1961, a variety of transformations has been developed, providing a photochemical alternative to classical Diels–Alder chemistry. However, enantioselective catalytic versions of the photenolization/Diels–Alder sequence have remained elusive until recently. This review describes how the field of enantioselective organocatalysis has provided suitable tools to stereoselectively trap photochemically generated hydroxy‐ o ‐quinodimethanes. Recent studies have also demonstrated that the chemistry is not limited to cycloaddition‐type manifolds, but can be expanded in order to develop intermolecular enantioselective addition processes.