Competing Michael/Anti-Michael Addition of Silyl Ketene Acetals to β-Nitrostyrenes Incorporating an Electron-Withdrawing Group.

ABSTRACT: β-Nitrostyrenes are archetypal Michael acceptors due to the strong electron-withdrawing nature of the nitro group. However, we found that β-nitrostyrenes substituted with electron-withdrawing groups react with silyl ketene acetals, activated by stoichiometric Lewis bases (K₂CO₃ or TBAF), to produce a mixture of Michael addition (M) and anti-Michael addition (AM) products. The yield strongly depends on the position and nature of the electron-withdrawing group within the phenyl ring (e.g., p-nitro: 8% AM 2% M; o-nitro 70% AM, 26% M). The formation of the unexpected AM product cannot be explained by a higher electrophilicity of the α-carbon compared to the β-carbon (Parr's indexes). Furthermore, we demonstrated that the formation of the AM product is not in

SUBMITTER: Martinez-Aguirre MA 

PROVIDER: S-EPMC12519467 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature