The Rh(II)-catalyzed formal [3+2] and [3+3] cycloadditions of 1-tosyl 1,2,3-triazoles with 2H-azirines have been developed, which enable the efficient synthesis of polysubstituted 3-aminopyrroles and 1,2-dihydropyrazines, respectively. The reported [3+2] cycloaddition represents the first application of 1-sulfonyl 1,2,3-triazole as a [2C]-component in relevant cycloaddition reactions.

In the title compound, C(33)H(32)N(2)O(2), the polysubstituted piperidine ring adopts a chair conformation. The isoxazolidine ring is in an envelope conformation. In the crystal structure, intra- and inter-molecular C-H⋯π inter-actions involving the phenyl rings are observed.

2-Pyrrolines can be generated by the PhP(2-catechyl) mediated coupling of alkene-tethered imines and acid chlorides. This reaction proceeds via phosphorus-containing 1,3-dipoles, which undergo cycloaddition with alkenes with high stereo- and regioselectivity. The modularity of this reaction can be used to assemble a range of polysubstituted pyrrolines in one pot transformations.

A route to cationic tungsten alkylidyne N-heterocyclic carbene (NHC) complexes of the general formula [W(CR)X2(NHC)(tBuCN)y+B(ArF)4–] (R = tBu, C6H4-4-OMe; X Br, Cl, OTf; NHC 1,3-dimesityl-1,3-dihydro-2H-imidazol-2-ylidene, IMes; 1,3-bis(2,6-diisopropylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene, IDipp; 1,3-dimesityl-4,5-dichloro-1,3-dihydro-2H-imidazol-2-ylidene, IMesCl2; y 1, 2; ArF 3,5-bis(tri...

treatment of acetyl- 1,4-benzoquinone with isoprene gave the corresponding regioselective adduct (i). rearrangement of the adduct (1) in pyridine and methanol gave 2-acetyl-5, 8-dihydro-6-methyl- 1,4-dihydroxynaphthalene (2). silver oxide oxidation of the rearranged product (2) gave 2-acetyl-5,8-dihydro- 6-methyl- 1,4naphthalenedione (3). regioselective addition of trans-piperylene to this comp...

Phosphotungstic acid (H(3)PW(12)O(40)) was used as an efficient and recyclable catalyst for the synthesis of polysubstituted quinolines through the Friedländer condensation of 2-aminoarylketone with carbonyl compounds, which was achieved by conventional heating under solvent-free conditions.

A novel and efficient cascade annulation of tertiary α-hydroxy ketones and dimethyl but-2-ynedioate is reported. The reaction, which only requires a base as the promoter, provides a straightforward access to polysubstituted pyrano[4,3-a]quinolizine-1,4,6(2H)-triones and 2H-pyran-2,5(6H)-diones under very mild reaction conditions.