Daniela Intrieri

[Ru(TPP)CO]‐Catalysed Intramolecular Benzylic CH 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.

Ruthenium porphyrins-catalyzed atom-efficient amination of C-H bonds by arylazides

Benzylic amines are synthesized in yield up to 90% by the Ru(TPP)CO-catalyzed amination of both exocyclic and endocyclic benzylic C-H bonds. The choice of arylazides as nitrogen sources confers to the methodology a good sustainability due to the formation of molecular nitrogen as the only stoichiometric by-product. A preliminary mechanistic investigation evidenced a critical role of the hydrocarbon concentration to drive the chemoselectivity of the reaction.

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).

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

The use of diazo reagents of the general formula N2C(R)(R1) 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 N2 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. The catalytic performances of different metal porphyrins are discussed and have been related to the structural features of the ligand with the final aim of rationalizing the strict correlation between the three-dimensional structure of the porphyrin ligand and the stereoselectivity of carbene transfer reactions.

Synthesis in mesoreactors: Ru(porphyrin)CO-catalyzed aziridination of olefins under continuous flow conditions

The Ru(porphyrin)CO-catalyzed addition of aryl azides to styrenes to afford N-aryl aziridines was successfully performed for the first time in mesoreactors under continuous flow conditions. Mesofluidic technology allowed for a rapid screening of different parameters and a quick identification of the optimized reaction conditions.

Correction: Organic azides: “energetic reagents” for the intermolecular amination of C–H bonds

Correction for ‘Organic azides: “energetic reagents” for the intermolecular amination of C–H bonds’ by Daniela Intrieri et al., Chem. Commun., 2014, DOI: 10.1039/c4cc03016h.

Synthesis, characterisation and catalytic use of iron porphyrin amino ester conjugates

The present study deals with the synthesis and characterisation of C2-symmetrical chiral Fe(III)(porphyrin)(OMe) catalysts; these catalysts display a totem structure, where each section is assigned to have a specific catalytic activity. The chiral portions of the porphyrin ligand are constituted by amino acid residues, which form a chiral cavity by surrounding both faces of the porphyrin plane, as clearly displayed by the X-ray structure of a free-base porphyrin. The Fe(III)(porphyrin)(OMe)-catalysed cyclopropanation of α-methylstyrene by diazo compounds occurred with excellent diastereoselectivities and a modest enantiocontrol. Thus, the obtained catalytic results have been rationalised by performing a DFT investigation and will be fundamental in the future modification of the molecular structure of chiral ligands to improve their catalytic performance.

Synthesis and catalytic activity of μ-oxo ruthenium(IV) porphyrin species to promote amination reactions

This work describes the synthesis of ruthenium(IV) μ-oxo porphyrin complexes of general formula [RuIV(TPP)(X)]2O which have been applied as catalysts in nitrene transfer reactions using aryl azides (ArN3) as nitrene sources. Collected data indicated that the catalytic efficiency of [RuIV(TPP)(OCH3)]2O was comparable to that of RuII(TPP)CO because of their analogous reactivity towards aryl azides to give the same catalytically active bis-imido species RuVI(TPP)(ArN)2. The reaction of [RuIV(TPP)(OCH3)]2O with Ph3CN3 or (CH3)3SiN3 afforded [RuIV(TPP)(N3)]2O which was fully characterised, its molecular structure was also determined by single crystal X-ray analysis.

From anilines to aziridines: A two-step synthesis under continuous-flow conditions

The Sandmeyer reaction of anilines to generate aryl azides, followed by the Ru(porphyrin)CO-catalyzed addition to styrenes affording N-aryl aziridines was successfully performed for the first time in mesoreactors, under continuousflow conditions. Mesofluidic technology allowed for a rapid screening of different parameters and a quick identification of the optimized reaction conditions for the two separate steps. The two optimized reactions were then combined in a single continuous process that allowed a safe and efficient synthesis of N-arylaziridines from convenient commercially available starting materials.

Recent advances in C–H bond aminations catalyzed by ruthenium porphyrin complexes

This review deals with the use of ruthenium porphyrin complexes to catalyze hydrocarbon aminations. This class of versatile porphyrin catalysts are able to activate different nitrogen sources, such as iminoiodinanes and organic azides, and promote the synthesis of a variety of aza-derivatives. Many synthetic procedures have been discussed as well as catalytic mechanisms involved in order to give an overview on the use of ruthenium porphyrins to promote nitrene transfer reactions yielding aminated derivatives.