title: Catalytic Enantioselective α,β,γ-Trioxygenation.
abstract: Applying a catalytic enantioselective aldehyde α-oxygenation condition to an enal substrate led to the discovery of the first α,β,γ-trifunctionalization cascade of enals. Under optimal conditions, a tryptophan-derived imidazolidinone catalyst in fluorinated aromatic solvents provided α,β,γ-trioxyaldehydes in up to 51% isolated yield (average of 80% yield per oxygenation step) and 85:15 er. Substitution at the δ position was tolerated, but not at the α, β, or γ positions. The reaction proceeded through initial TEMPO incorporation at the γ position, and rapid racemization of this intermediate, reversible conjugate addition of water, followed by TEMPO incorporation at the α position to set all three stereocenters with double dynamic kinetic resolution.
authors.affiliation: Department of Chemistry, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Gayan A
authors.initials: GA
authors.lastname: Abeykoon
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D003497:Cyclic N-Oxides / Q000737:chemistry*; D048289:Imidazolidines / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D013237:Stereoisomerism; D014364:Tryptophan / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000447:Aldehydes; D003497:Cyclic N-Oxides; D048289:Imidazolidines; C004916:ethylene urea; D014364:Tryptophan; C003959:TEMPO