Synthesis of oxepine-, oxocine- and azepine-annulated carbazole derivatives by combined Claisen rearrangement and diene/enyne metathesis

Regioselective access of alkylidendibenzo[c,f]oxocine framework via cyclocarbopalladation/cross-coupling cascade reactions and reductive Heck strategy

Palladium-catalyzed dual strategies of cascade cyclocarbopalladation/cross-coupling of alkynes and a reductive Heck reaction have been developed to construct dibenzo[c,f]oxocine frameworks with tri- and tetra-substituted exo-cyclic alkenes with high stereo- and regio-control.

Diversity-Oriented Approaches to Polycyclics and Bioinspired Molecules via the Diels-Alder Strategy: Green Chemistry, Synthetic Economy, and Beyond

We describe diverse approaches to various dienes and their utilization in the Diels-Alder reaction to produce a variety of polycycles. The dienes covered here are prepared by simple alkylation reaction or via the Claisen rearrangement or by enyne metathesis of alkyne or enyne building blocks. Here, we have also included the Diels-Alder chemistry of dendralenes, a higher analog of cross-conjugated dienes. The present article is inclusive of o-xylylene derivatives that are generated in situ starting with benzosultine or benzosulfone derivatives. The Diels-Alder reaction of these dienes with various dienophiles gave diverse polycyclic systems and biologically important targets.

Synthesis and biological evaluation of fused oxepinocoumarins as free radicals scavengers

Some fused dihydrooxepino[f]-, [g]-, and [h]coumarins were obtained from the ring-closing metathesis of the corresponding o-allyl-allyloxycoumarins under the treatment with the first generation Grubbs' catalyst. These compounds were tested in vitro for their antioxidant activity, and they present significant scavenging activity. They were also showed to inhibit in vitro soybean lipoxygenase.

Access to unusual polycyclic spiro-enones from 2,2'-bis(allyloxy)-1,1'-binaphthyls using Grubbs' catalysts: an unprecedented one-pot RCM/Claisen sequence

Treatment of 2,2'-bis(allyloxy)-1,1'-binaphthyls with the first-generation Grubbs' carbene under MW-irradiation results in the formation of new polycyclic spiro-enones through an unprecedented RCM/Claisen sequence.

6-Methyl-2,3,4,9-tetra-hydro-1H-carbazole-1-thione

In the title mol­ecule, C₁₃H₁₃NS, the dihedral angle between the benzene ring and the fused pyrrole ring is 0.71 (8)° and the cyclo­hexene ring is in an envelope form. The (CH₂)₃ atoms of the cyclo­hexene ring are disordered over two positions; the site-occupancy factor for the major component refined to 0.862 (4). In the crystal, inter­molecular N—H⋯S hydrogen bonds lead to the formation of centrosymmetric aggregates via an R₂²(10) ring.

Advanced approach to polycyclics by a synergistic combination of enyne metathesis and Diels-Alder reaction

Enyne metathesis (EM) has widely been used to prepare various synthetic and natural products. Further, a sequential use of EM and Diels-Alder (DA) reactions generates highly functionalized and intricate polycarbocycles and heterocyclic frameworks. In this critical review we describe the application of a unique combination of EM and DA reactions to prepare various amino acid derivatives, natural products and heterocycles. Some of the heterocyclic targets include cyclic peroxides, siloxanes and various nitrogen (or oxygen) containing compounds. Use of ethylene and cyclooctadiene (COD) for improving the yield of EM products are also discussed (69 references).