The microwave-promoted alkoxycarbonylation of aryl iodides using reaction vessels pre-pressurized with carbon monoxide is reported. Reactions are performed using 0.1 mol% palladium acetate as catalyst, DBU as base and are complete within 20-30 min. A range of aryl iodide substrates can be converted to the corresponding esters using this methodology. Primary and secondary alcohols work well wher...

The stereoselective transformation of α-alkoxyacetoaldehydes to the corresponding (Z)-vinyl triflates was achieved by treatment with phenyl triflimide and DBU. The stereochemistry was explained by the "syn-effect," which was attributed primarily to an σ → π* interaction. The β-alkoxy vinyl triflates obtained were applied to the stereoselective synthesis of structurally diverse (Z)-allylic alcoh...

New bis-(oxazolyl)pyridine ligands for Ln(III) ions were prepared using a expeditious methodology from threonine and dipicolinic acid chloride. The synthetic strategy includes a dehydration step to give a bis-dehydroaminobutyric acid derivative followed by bromination and cyclization with DBU. Photophysical studies of Eu(III) and Tb(III) complexes of these ligands showed that the 2,6-bis-(oxazo...

Starting from easily accessible gem-difluoropropargylic derivatives, a DBU-mediated isomerisation affords enones in fair yields with a gem-difluoroalkyl chain. These derivatives were used to prepare pyrazolines and pyrrolines with the desired gem-difluoroalkyl side chain by cyclocondensations in good yields and with excellent stereoselectivity. A one-pot process was also successfully developed ...

A practical Pd(PPh3)4/DBU catalytic system for the synthesis of pharmaceutically relevant aminopyridine nitrile intermediates, as well as a variety of other aryl nitriles using non-toxic K4[Fe(CN)6] has been developed. The key features of our new protocol for cyanation lie in that the reaction can be carried out with readily available Pd(PPh3)4 under mild and green conditions, even without the ...

An efficient synthesis of 4-arylcoumarins has been accomplished via Kostanecki reactions of 2-hydroxybenzophenones with acetic anhydride employing DBU at ambient temperature. Using the same strategy, several 2-acyloxybenzophenone derivatives were readily converted to 3,4-difunctionalized coumarins. This protocol offers a notable improvement in reaction conditions for coumarin synthesis and take...

The first total synthesis of gelsemoxonine (1) has been accomplished. Divinylcyclopropane-cycloheptadiene rearrangement of the highly functionalized substrate was successfully applied to assemble the spiro-quaternary carbon center connected to the bicyclic seven-membered core structure. A one-pot isomerization reaction of the α,β-unsaturated aldehyde to the saturated ester via the TMSCN-DBU rea...

Microwave-assisted unimolecular isomerization-Claisen domino reactions of 1,3-di(hetero)aryl propargyl trityl ethers lead, depending on the basicity of the amine, either to the formation of tricyclo[3.2.1.0(2,7)]oct-3-enes (with triethylamine) or to indanes (with DBU). Based upon product analyses and computations, this base dependent dichotomy can be rationalized as a sequel of pericyclic react...

Herein, we report the use of acid/base complexes for the ring opening polymerization of (L)-lactide. The salt formed from an equimolar reaction of benzoic acid and DBU produced a catalyst capable of controlled polymerizations allowing for targeted molecular weights and narrow polydispersities. The use of computational analysis suggests a bifunctional catalytic mechanism wherein both the monomer...