Indoles from Alkynes and Aryl Azides: Scope and Theoretical Assessment of Ruthenium Porphyrin-Catalyzed Reactions.

A symbiotic experimental/computational study analyzed the Ru(TPP)(NAr) -catalyzed one-pot formation of indoles from alkynes and aryl azides. Thirty different C -substituted indoles were synthesized and the best performance, in term of yields and regioselectivities, was observed when reacting ArC≡CH alkynes with 3,5-(EWG) C H N azides, whereas the reaction was less efficient when using electron-rich aryl azides. A DFT analysis describes the reaction mechanism in terms of the energy costs and orbital/electronic evolutions; the limited reactivity of electron-rich azides was also justified.

Synthesis of a Family of Highly Substituted Porphyrin Thioethers via Nitro Displacement in 2,3,7,8,12,13,17,18-Octaethyl-5,10,15,20-tetranitroporphyrin.

A series of highly substituted porphyrin thioethers was synthesized from 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetranitroporphyrin (HOETNP). The reactions proceeded via a SAr mechanism with a broad range of aromatic thiols in the presence of a base. This is a rapid way to prepare a large variety of meso-substituted porphyrins from only one precursor.

The ligand influence in stereoselective carbene transfer reactions promoted by chiral metal porphyrin catalysts.

The use of diazo reagents of the general formula NC(R)(R) as carbene sources to create new C-C bonds is of broad scientific interest due to the intrinsic sustainability of this class of reagents. In the presence of a suitable catalyst, diazo reagents react with several organic substrates with excellent stereo-control and form N as the only by-product. In the present report the catalytic efficiency of metal porphyrins in promoting carbene transfer reactions is reviewed with emphasis on the active role of the porphyrin skeleton in stereoselectively driving the carbene moiety to the target substrate.

Organic azides: "energetic reagents" for the intermolecular amination of C-H bonds.

This feature article provides an overview of the application of organic azides for the intermolecular amination of sp(3) and sp(2) C-H bonds. The catalytic activity of several metal complexes was reviewed underlining both synthetic and mechanistic aspects of the C-H amination. The majority of the aminated compounds reported in literature have been collected in this paper to provide a compendium of published procedures.

Highly diastereoselective cyclopropanation of α-methylstyrene catalysed by a C2-symmetrical chiral iron porphyrin complex.

A new chiral iron porphyrin-based catalyst performed α-methylstyrene stereoselective cyclopropanation with excellent yields (up to 99%), enantio- and diastereoselectivities (ee(trans) up to 87%, trans/cis ratios up to 99 : 1) and outstanding TON and TOF values (up to 20,000 and 120,000 h(-1) respectively).

[Ru(TPP)CO]-catalysed intramolecular benzylic C-H bond amination, affording phenanthridine and dihydrophenanthridine derivatives.

Shedding light on azides: [Ru(TPP)CO] (TPP=tetraphenyl porphyrin dianion), white light and O(2) were found to be a suitable catalyst combination to perform the annulation of several biaryl azides. The high chemoselectivity of the process allows the synthesis of phenanthridines and dihydrophenanthridines in good yield and purity.