Enantioselective Organocatalytic Aryloxylation of Aldehydes with o-Quinones

Significance Here the authors report a direct enantioselective organocatalytic aryloxylation of aldehydes via an inverse-electron-demand hetero-Diels-Alder reaction of in situ generated en­amines and o -quinone reagents. MacMillan’s imidazolidinone catalyst 1 has been found to be effective for this reaction and MeCN-H 2 O has been identified as the optimal solvent system. With 10 mol% of the catalyst, moderate to good yields (52-75%) and high enantioselectivities (er = 88:12 to 90:10) are obtained for different alkyl aldehydes.