A new Lewis acid-catalyzed endo-selective Prins bicyclization of γ,δ-unsaturated aldehydes or ketones with a broad range of aldehydes to dioxabicyclo[2.2.2]octanes is disclosed. When using a chiral BINOL-derived N-triflylphosphoramide (NTPA) as catalyst and glyoxylate esters as substrates, the cross-dimerization afford functionalized bicyclic acetals with excellent diastereo- and enantioselectivities.

In the presence of a Lewis acid, trimethylsilyl-substituted β,γ-unsaturated ketones and aldehydes (imines) undergo nucleophilic addition to produce zwitterionic intermediates, followed by oxy-2-oxonia(azonia)-Cope rearrangements to give homoallylic esters (amides). In the case of TMS-containing 2-vinylcycloalkanones, the process results in ring-enlargement, providing 10- to 16-membered lactones. This protocol was applied to the total synthesis of (R)-phoracantholide I.

A general method to synthesize functionalized allyl α-amino acid derivatives through an irreversible oxy-2-azonia-Cope rearrangement is reported. In the presence of AlCl₃, the reaction of imino ethyl glyoxalates with various β,γ-unsaturated ketones furnished the corresponding allyl α-amino acid derivatives. The key to the success of this method is the amide bond formation, which makes the rearrangement irreversible. This reaction system constitutes a new strategy for the synthesis of unusual allyl glycine derivatives, which are valuable synthetic intermediates. An efficient and operationally simple three-component version of this reaction was also performed.

Simple allenyl ethers have been shown to be efficiently activated by cationic gold(I) catalysts to form reactive dienophiles in intermolecular Diels–Alder reactions. A range of different dienes give the cycloaddition products in moderate to excellent yields and good selectivity.

The Diels-Alder reactions of ethyl α-bromoacrylate 1 with open-chain dienes 2 were conducted under thermal or Lewis acid-catalysis conditions. In most cases, the cyclic adducts of 1-bromocyclohex-3-enecarboxylates 3 were formed in high yields with good regio- and stereoselectivity. Subsequent E2-elimination by treatment with DBU provided the corresponding 1,3- or 1,4-cyclohexadienecarboxylates depending on the relative configuration of the products. Starting from myrcene (7-methyl-3-methyleneocta-1,6-diene) the reaction sequence afforded the ester precursor of Georgywood with good yields.

PBBTZ (6H-pyrrolo[3,2-b:4,5-b′]bis[1,4]benzothiazine) was a p-type semiconductor with high field-effect transistor (FET) performance that we have just reported. Two trifluoromethyl substituted PBBTZ derivatives 3a and 3b were synthesized from facile one-pot condensation. They were characterized by means of ¹H NMR, IR, HRMS (EI-TOF) and elemental analysis, furthermore, the crystal structure of 3b was described and discussed. Their optical properties were studied by UV-Vis and fluorescence spectroscopy, electrochemical properties were investigated by cyclic voltammetry (CV), and thermal properties were evaluated by thermal gravimetric analysis (TGA). The energy gaps of 3a and 3b, taken directly from spectroscopic measurements, are as broad as 2.45 and 2.48 eV, leading to bluish green and green photoluminescence. The LUMO and HOMO energy levels are −5.73 and −3.28 eV for 3a, −5.67 and −3.19 eV for 3b, respectively. The low energy levels render them well air-stable, and to be promising n-type semiconductor candidates for use in organic electronics.

An efficient palladium-catalyzed amination of aryl halides with amines, using rac-P-Phos as the ancillary ligand and Pd(OAc)₂ as the palladium source is developed. The ligand and all of the synthetic intermediates are stable to air and moisture, allowing the easy handling. The catalyst system performed well for a large number of different substrate combinations in 80–110°C to furnish aromatic amines in high yields.

A novel construction of 2-benzazepine derivatives based on TiCl₄-mediated tandem Mannich reaction of electron-rich benzyl iminium ions with alkenyl ethers and Friedel–Crafts-type alkylation is described. The protocol is amenable to provide the tricyclic furo[3,2-d][2]benzazepine and pyrano[3,2-d][2]benzazepine derivatives, respectively, with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran as the substrates.

This article describes the design and optimization of an effective organocatalytic three-component domino α-methylenation/Diels–Alder reaction to produce vinyl-substituted cyclohexenecarboxaldehydes in a highly regioselective fashion. In these one-pot transformations, 2-formyl-1,3-butadienes (4) were prepared in situ from α,β-unsaturated aldehydes and formalin and were subsequently trapped with a variety of buta-1,3-dienes. The outcomes of the reactions were dependent on the electronic properties of the dienes. 1-Vinylcyclohexenecarbaldehydes 6 were formed by use of acyclic electron-rich dienes, while the initially formed cycloadducts of 4 with cyclopentadiene underwent Cope rearrangements, leading to the formation of tetrahydro-3H-indene-5-carbaldehyde compounds 7. The mechanisms involved in these reactions were deduced from experimental findings. Furthermore, the method was also extended to one-pot domino methylenation/Diels–Alder reactions of dihydrofurans and dihydropyrans to yield spirocyclic lactols 22. In these reactions, the unstable intermediate hydroxyethyl and hydroxypropyl acroleins behaved as dienophiles, undergoing cycloaddition reactions with dienes with good yields and selectivities. The wide variety of functionalized 1-vinylcyclohex-3-enecarbaldehydes 6, 4-vinylcyclohex-1-enecarbaldehydes 7, and spiro lactols 22 generated through the use of these organocatalytic domino processes as a diversity-oriented synthesis provided useful intermediates for the construction of novel odorants.