Diastereoselective synthesis of chiral 3-substituted isoindolinones via rhodium(III)-catalyzed oxidative C-H olefination/annulation

A new method for the direct and stereoselective synthesis of 3-substituted isoindolinones via Rh(III)-catalyzed chiral N-sulfinyl amide directed asymmetric [4+1] annulation of benzamides with acrylic esters is developed. The reaction...

Halide Anion Activated Reactions of Michael Acceptors with Tropylium Ion

Tropylium bromide undergoes non-catalyzed, regioselective additions to a large variety of Michael acceptors. In this way, acrylic esters are converted into ß-bromo-α-cycloheptatrienyl-propionic esters. The reactions are interpreted by nucleophilic attack of bromide ions at the electron-deficient olefins and trapping of the incipient carbanion by the tropylium ion. Quantum chemical calculations were performed to elucidate the analogy to the amine or phosphine-catalyzed Rauhut-Currier reactions. Subsequent synthetic transformations of the bromo-cycloheptatrienylated adducts are reported.

Halide Anion Activated Reactions of Michael Acceptors with Tropylium Ion

Tropylium bromide undergoes non-catalyzed, regioselective additions to a large variety of Michael acceptors. In this way, acrylic esters are converted into ß-bromo-α-cycloheptatrienyl-propionic esters. The reactions are interpreted by nucleophilic attack of bromide ions at the electron-deficient olefins and trapping of the incipient carbanion by the tropylium ion. Quantum chemical calculations were performed to elucidate the analogy to the amine or phosphine-catalyzed Rauhut-Currier reactions. Subsequent synthetic transformations of the bromo-cycloheptatrienylated adducts are reported.

One-Pot Synthesis of α-Substituted Acrylates

A simple and efficient synthetic method towards α-substituted acrylic esters has been developed using the Horner–Wadsworth–Emmons (HWE) reaction with HCHO after alkylation of phosphonoacetates in a one-pot reaction. This method allows the smooth introduction of various side-chains, such as natural amino acids and other biologically relevant substituents. The use of mild conditions, inexpensive reagents, short reaction times and simple work-up and purification steps provides an effective and general alternative to cumbersome multistep and low-yielding procedures described to date.