Bifunctional Brønsted Base Catalyst Enables Regio-, Diastereo-, and Enantioselective C<sub>α</sub>-Alkylation of β-Tetralones and Related Aromatic-Ring-Fused Cycloalkanones
The catalyticasymmetric synthesis of both α‐substituted and α,α‐disubstituted (quaternary) β‐tetralones through direct α‐functionalization of the corresponding β‐tetralone precursor remains elusive. A designed Brønsted base‐squaramide bifunctionalcatalyst promotes the conjugate addition of either unsubstituted or α‐monosubstituted β‐tetralones to nitroalkenes. Under these reaction conditions, not
The Michael addition to nitroolefins of manganese enolates derived from an array of ketones is reported. The desired 1,4-adducts are obtained in high yield and excellent diastereo- and regioselectivity, the sole kinetic adduct being obtained in the case of nonsymmetrical ketones. The effect of a thiourea-type organocatalyst on the addition of several representative nitroolefins to the kinetic manganese enolate derived from isopropyl ethyl ketone is also reported.