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An efficient synthesis of quinazotin-4(3H)-ones from N-arylamidines, through palladium-catalyzed intramolecular C(sp²)-H carboxamidation, has been developed. The reaction, carried out in the presence of 1.0 equiv of CuO as oxidant under atmospheric pressure of CO, provides diversified 2-aryl(alkyl)-quinazolin-4(3H)-ones in reasonable to good yields from N-aryla-midines, which are readily derived from anilines and nitriles. Compared with existing approaches to quinazolin-4(3H)-ones, the current strategy features atom-economy and step-efficiency. [ABSTRACT FROM AUTHOR]

The Diels-Alder (DA) reactions of various substituted ethenes (methyl vinyl ether (MVE), styrene, and methyl vinyl ketone (MVK)) with o-quinone methides (o-QM) are studied by means of density functional theory (DFT) at the B3LYP/6-31G(d,p) level. On the basis of analysis for frontier molecular orbital and comparison of the activation energies for different reaction pathways, the ortho attack modes present transition structures more stable than the meta ones. The reactivity, ortho selectivity, and asynchronicity are enhanced with the increase of the electron-releasing character of the substitute on ethene fragment. The discussions for the charge distribution and charge transfer on different transition states indicate that there are different molecular mechanisms for the different substituted ethenes. The calculations show that the effect of solvent decreases the activation energy and increases the asynchronicity. The results also indicate that the hydrogen-bond formation between chloroform and the carbonyl oxygen of the o-QM lowers the activation energies and increases the asynchronicity. [ABSTRACT FROM AUTHOR]

Reports on the total synthesis of microtubule-stabilizing agent (-)-laulimalide. Synthetic strategy; Dihydropyran ring of fragment; Reduction of alkynyl alcohol.

A series of chiral β-aryl-substituted γ-amino butyric acid derivatives were synthesized in good enantioselectivities via the Cu-catalyzed asymmetric conjugate reduction of γ-phthalimido-α,β-unsaturated carboxylic acid esters using Cu(OAc)2·H2O as a catalyst precursor, (S)-BINAP as a ligand, PMHS as a hydride source, and t-BuOH as an additive. The methodology has been applied successfully to the enantioselective synthesis of a chiral pharmaceutical, (R)-baclofen. [ABSTRACT FROM AUTHOR]

Diversified 2-alkoxy- and 2-aroxy-3-substituted quinolines were synthesized from o-alkynylaryl isocyanides and alcohols and phenols promoted by DABCO, respectively. The reaction was initiated by nucleophilic addition of DABCO to isocyanide and subsequent cycliztion, leading to a DABCO-quinoline-based adduct as the reactive intermediate, followed by substitution of the DABCO moiety with oxygenated nucleophiles. [ABSTRACT FROM AUTHOR]