We show here the first radical route for the direct photosynthesis of AuCN oligomers with different sizes and shapes, as evidenced by TEM observations, from an Au nanoparticle/benzaldehyde/CH(3)CN ternary system in air under UV-light irradiation. This photochemical route is green, mild, and universal, which makes itself distinguishable from the common cyanidation process. Several elementary reaction steps, including the strong C-C bond dissociation of CH(3)CN and subsequent •CN radical addition to Au, have been suggested to be critical in the formation of AuCN oligomers based on the identification of •CN radical by in situ EPR and the radical trapping technique, and other reaction products by GC-MS and (1)H NMR, and DFT calculations. The resulting solid-state AuCN oligomers exhibit unique spectroscopic characters that may be a result of the shorter Au-Au distances (namely, aurophilicity) and/or special polymer-like structures as compared with gold cyanide derivatives in the aqueous phase. The nanosized AuCN oligomers supported on mesoporous silica showed relatively good catalytic activity on the homogeneous annulation of salicylaldehyde with phenylacetylene to afford isoflavanones employing PBu(3) as the cocatalyst under moderate conditions, which also serves as evidence for the successful production of AuCN oligomers.
Novel palladium-catalyzed carboannulation reactions of arynes with functionalized vinyl iodides are reported. By applying allyl-substituted iodocycloenones and iodofuranones, a series of hydrophenanthren-1(2H)-ones and naphthoA C H T U N G T R E N N U N G [2,1-c]furan-3(1H)-ones were efficiently constructed in one pot under mild conditions.
-This methodology provides an efficient route to a variety of polysubstituted naphthalene derivatives, which would have potential utilization in the construction of bioactive compounds and valuable building blocks. -(HUANG*, X.; SHA, F.; TONG,
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