Synthesis of α,β-Disubstituted Acrylates via Galat Reaction

Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)

The use of mono-substituted malonic acid half oxyesters (SMAHOs) has been hampered by the sporadic references describing their preparation. An evaluation of different approaches has been achieved, allowing to define the best strategies to introduce diversity on both the malonic position and the ester function. A classical alkylation step of a malonate by an alkyl halide followed by a monosaponification gave access to reagents bearing different substituents at the malonic position, including functionalized derivatives. On the other hand, the development of a monoesterification step of a substituted malonic acid derivative proved to be the best entry for diversity at the ester function, rather than the use of an intermediate Meldrum acid. Both these transformations are characterized by their simplicity and efficiency, allowing a straightforward access to SMAHOs from cheap starting materials.

Decarboxylative Mannich Reactions with Substituted Malonic Acid Half-Oxyesters

The decarboxylative Mannich reaction between imines and substituted malonic acids half-oxyesters (SMAHOs) has been developed using 1,4-diazabicyclo[2.2.2]octane (DABCO) as an organocatalyst. The reaction proceeds under simple reaction conditions and tolerates a broad range of substrates, affording general access to β^2,3-aminoesters, the syn diastereomer being the major one. An alternative multicomponent protocol has also been developed to increase the overall eco-compatibility of the process.