Enantioselective organocatalytic aldol reaction of ynones and its synthetic applications.
[Structure: see text] For the first time, unmodified ynones were used in organocatalytic asymmetric aldol reactions delivering monoprotected anti-alpha,beta-dihydroxyynones in high yields, dr's up to 19:1, and ee's up to 95%. These products can be either reduced to afford enantioenriched unsaturated anti,anti-triol or cyclized using a novel intramolecular phosphine-catalyzed alpha-addition to the ynone. This organocatalytic sequential aldol-cyclization process provides a concise entry to unusual enantioenriched oxygenated heterocycles, which can be used for subsequent structural manipulations.
Silva
Franck
F
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, UK.
Sawicki
Marcin
M
Gouverneur
Véronique
V