Direct synthesis of stereodefined and functionalized dienes as valuable building blocks.

We have reported a direct and stereoselective synthesis of functionalized dienoic carboxylates from the simple bicyclic lactone 1. The use of oxygen- or nitrogen-based nucleophiles in a domino allylic alkylation/4π-electrocyclic ring opening affords reliable access to dienes with interesting functionalities. Alternatively, halide substitution offers synthesis of other classes of functionalized dienoic acids. Herein, we demonstrate the utility of such dienoic products as key building blocks in various transformations as well as natural product synthesis.

Stereoselective synthesis of dienyl-carboxylate building blocks: formal synthesis of inthomycin C.

A direct synthesis of stereodefined halodienes is reported. Those key building blocks enable a concise access to polyenic products, as demonstrated in a modular synthesis of Inthomycin C.

An atom-economical and stereoselective domino synthesis of functionalised dienes.

Open sesame: A direct synthesis of functionalised and stereodefined dienes, relying on a domino allylic alkylation/electrocyclic ring-opening sequence, is reported. This method allows concise access to doubly vinylogous esters. A further systematic study of ring-opening rates of carbon-substituted cyclobutenes allowed the design of substrates amenable to sequential pericyclic reactions (see scheme).

Catalytic asymmetric diastereodivergent deracemization.

Your wish is my command: Deracemization is a powerful strategy wherein a racemate is converted into a 100 % yield of a single enantiopure product. A new concept in catalytic deracemization is presented, in which a racemate with n stereogenic elements can be selectively converted into each one of 2(m) (m = number of chiral centers of the product) different enantiopure products, by simple tuning of the reaction conditions.

A concise access to 3-substituted 2-pyrones.

The development of a modular synthesis of 3-substituted-2-pyrones is described. The attainment of this strategy hinges on a new electrophilic pyrone derivative which can be readily prepared on a multigram scale and which performs very competently in metal-catalyzed cross-coupling reactions with a variety of nucleophiles.

Concise enantioselective synthesis of ent-malbrancheamide B.

A concise enantioselective synthesis of the fungal metabolite ent-malbrancheamide B was accomplished through the union of a C-prenylated proline derivative and a substituted indole pyruvic acid SEM enol ether, followed by a cationic double cyclization as the key step.