Chiral enamides, easily prepared in one step from a cyclic ketone and an oxazolidinone, are successfully employed in high-yielding, endo, and facially selective Hetero-Diels−Alderreactions involving activated oxadienes and Siever’s reagent as catalyst. From the resulting bicyclic heteroadducts, a novel and efficient asymmetric modification for the Robinson annulation of cyclic monoketones is described
Highlyenantioselective cross‐aldol reactions between acetaldehyde and activated acyclic ketones are reported for the first time. Various acyclic ketones, such as saturated and unsaturated keto esters, reacted with acetaldehyde in the presence of a chiral primaryamine and a Brønsted acid to afford optically enriched tertiary alcohols in good yields and with excellent enantioselectivities. Trifluoromethyl