Intermolecular Aryne Ene Reaction of Hantzsch Esters: Stable Covalent Ene Adducts from a 1,4-Dihydropyridine Reaction.

The reaction of arynes with 1,4-dihydropyridines affords 2-aryl-1,2-dihydropyridines or 2-methylene-3-aryl-1,2,3,4-tetrahydropyridines via a regioselective C-2 or C-3 arylation. These compounds are the first series of isolable and bench-stable covalent ene adducts formed between dihydropyridines and unsaturated substrates. Experimental studies and DFT calculations provide mechanistic support for a concerted intermolecular aryne ene process, which may have implications for NAD(P)H model reactions.

Binuclear β-diketiminate complexes of copper(i).

The reaction of a series of dinucleating bis(β-diketiminate) pro-ligands with mesitylcopper in the presence and absence of mono and diphosphines has allowed the isolation of a new series of dicopper(i) complexes. Inclusion of trans-1,2-cyclohexyl (1), 2,6-pyridyl (2), and 2,2'-oxydiaryl (3) spacers between the β-diketiminate units has been studied. The isolation of three new copper(i) phosphine complexes [1·Cu2(PPh3)2], [2·Cu2(PPh3)2] and [3·Cu2(PPh3)2] is reported.

Synthesis and reactivity of electron poor allenes: formation of completely organic frustrated Lewis pairs.

The synthesis of several electron poor allenes bearing electron withdrawing substituents is described and their use as Lewis acids in the field of frustrated Lewis pair (FLP) chemistry reported. At room temperature the combination of N-heterocyclic carbenes (NHC) with the allenes under study invariably afforded the corresponding Lewis adducts; however, at -78 °C this reaction is in most of the cases inhibited and kinetically induced organic FLPs are formed. Under these conditions the activation of S-S bonds in disulfides has been achieved in excellent yields.

Decreased optical nonlinearities upon CF3 substitution on tricyanofuran acceptors.

Replacement of the tricyanofuran (TCF) acceptor by its stronger analogue CF 3-TCF results in decreased second-order optical nonlinearities in merocyanines bearing a proaromatic 1,3-dithiole donor. The TCF-containing derivatives display exceptionally high mu beta values up to 31,000 x 10(-48) esu, unprecedented for 1,3-dithiole-based NLO-phores.

Iodocarbocyclization reaction of beta-ketoesters and alkynes.

Iodocyclopentenes are formed at room temperature upon straight reaction of delta-alkynyl-beta-ketoesters with I2 for several hours. Cyclizations involving terminal and substituted (alkyl, aryl, Br, I) alkynes were accessed. Twelve examples with yields ranging from 20% up to 80% are reported (out of them eight cases are above 60%).