Multisubstituted arenes such as indanes with attached all-carbon quaternary centers are unique scaffolds in synthetic functional molecules and sophisticated natural products.Akey challenge in preparing such molecules lies in the enantioselective installation of the quaternary carbon centers.C onventional methods in this direction include asymmetric substitution reactions and substrate-controlled cyclization reactions.T hese reactions lead to poor stereoselectivities and/or require long and tedious synthetic steps.Disclosed here is ao ne-step organic catalytic strategy for enantioselective access to this class of molecules.T he reaction involves an Nheterocyclic carbene catalyzedp rocess for direct benzene construction, indane formation, remote-carbon desymmetrization, and excellent chirality control. This approach will enable the concise synthesis of arene-containing molecules,i ncluding those with complex structures and challenging chiral centers.

Access to all-carbon spirocycles through a carbene and thiourea cocatalytic desymmetrization cascade reaction

Topoisomerases (Topo I and Topo II) are very important players in DNA replication, repair, and transcription, and are a promising class of antitumor target. In present study, a series of benzo[a]phenazine derivatives with alkylamino side chains at C-5 were designed, synthesized, and their biological activities were evaluated. Most of derivatives showed good antiproliferative activity with a range of IC50 values of 1-10 μM on the four cancer cell lines HeLa, A549, MCF-7, and HL-60. Topoisomerase-mediated DNA relaxation assay results showed that derivatives could effectively inhibit the activity of both Topo I and Topo II, and the structure-activity relationship studies indicated the importance of introducing an alkylamino side chain. Further mechanism studies revealed that the compounds could stabilize the Topo I-DNA cleavage complexes and inhibit the ATPase activity of hTopo II, indicating that they are a rare class of dual topoisomerase inhibitors by acting as Topo I poisons and Topo II catalytic inhibitors. Moreover, flow cytometric analysis and caspase-3/7 activation assay showed that this class of compounds could induce apoptosis of HL-60 cells.

Access to all-carbon spirocycles through a carbene and thiourea cocatalytic desymmetrization cascade reaction

An N-heterocyclic carbene-catalyzed direct oxidative coupling of enals and di(hetero)arylmethanes allows for quick access to optical pure benzimidazole-fused lactams.