Rui M. B. Carrilho

Highly active phosphite gold(I) catalysts for intramolecular hydroalkoxylation, enyne cyclization and furanyne cyclization

New and highly active mononuclear phosphite gold(I) catalysts are described. Turn-over numbers up to 37,000 for the furan-yne reaction and up to 28,000,000 for the two-fold hydroalkoxylation of alkynes are reported.

A Cost-Efficient Method for Unsymmetrical Meso-Aryl Porphyrin Synthesis Using NaY Zeolite as an Inorganic Acid Catalyst

Herein we report the synthesis of unsymmetrical meso-aryl substituted porphyrins, using NaY zeolite as an inorganic acid catalyst. A comparative study between this method and the several synthetic strategies available in the literature was carried out. Our method presented a better, more cost-efficient rationale and displayed a significantly lower environmental impact. Furthermore, it was possible to verify the scalability of the process as well as the reutilization of the inorganic catalyst NaY (up to 6 times) without significant yield decrease. In addition, this method was applied to the synthesis of several other unsymmetrical porphyrins, from a low melting point porphyrin to mono-carboxylated halogenated unsymmetrical porphyrins, in yields higher than those found in the literature. Additionally, for the first time, two acetamide functionalized halogenated porphyrins were prepared in high yields. This methodology opens the way to the preparation of high yielding functionalized porphyrins, which can be easily immobilized for a variety of applications, either in catalysis or in biomedicine.

A recyclable hybrid manganese(III) porphyrin magnetic catalyst for selective olefin epoxidation using molecular oxygen

The synthesis and characterization of a hybrid Mn(III)-porphyrin magnetic nanocomposite is described. Moreover, a sustainable methodology for epoxidation of olefins is reported, using O2 as a green oxidant and the magnetic nanoparticle as a recyclable catalyst. High activity in alkene oxidation was observed, with full selectivity for epoxide formation. The magnetic catalyst presented high stability, being recovered and reused in five consecutive runs without loss of catalytic activity or selectivity in cyclooctene oxidation. Moreover, the catalytic system showed very good reactivity toward epoxidation of a range of terminal, substituted, cyclic or acyclic, aliphatic and aromatic olefins, including terpene and steroid derivatives, affording a range of biologically relevant epoxides in excellent yields. The isobutyric acid, formed as side-product, was recovered with high yield and purity, which provides the potential reutilization of this important industrial product.

A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis-N-heterocycles: rationalization by electronic structure calculations

An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N-nucleophiles, gives access, in one pot, to a new family of indole-based N-heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation (PCO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reactions selectivity, with the best yields for the cyclic products being obtained in the presence of (1S,2S)-(+)-cyclohexane-1,2-diamine (a) as the nucleophile, using either 5- or 7-iodoindole as the substrate. The reactions selectivity was rationalized based on electronic structure calculations, which explain the effect of the diamine structure on the predominant formation of the cyclic products.

Hybrid Metalloporphyrin Magnetic Nanoparticles as Catalysts for Sequential Transformation of Alkenes and CO2 into Cyclic Carbonates

The synthesis and full characterization of manganese and chromium metalloporphyrins and hybrid magnetic nanocomposites prepared thereof is described. Their application in homogeneous and heterogeneous sequential epoxidation/CO2 cycloaddition reactions by using O2 or H2O2 as the oxidant showed high activity and selectivity for the preparation of a variety of cyclic carbonates directly from olefins. The combination of manganese and chromium nanocomposites allowed us to set the keystone for the development of a reusable dual catalytic system to transform olefins into cyclic carbonates.

Tervalent phosphorus acid derivatives

This chapter covers the most relevant literature published during the year 2014, related to tervalent phosphorus acid derivatives. Some of the most relevant concepts are reported, regarding synthetic methodologies to halogenophosphorus compounds, phosphorus esters (phosphinite, phosphonite and phosphites), phosphorus amides (aminophosphines, phosphoramidites and diamidophosphites) and mixed phosphorus compounds bearing two different tervalent phosphorus moieties. A critical selection of their applications is briefly assessed, with an emphasis on the catalytic applications of ligands and metal complexes.

Chapter 2:Tervalent phosphorus acid derivatives

This chapter covers the most relevant literature related to tervalent phosphorus acid derivatives, published between January 2011 and December 2013. Some relevant concepts regarding the main synthetic routes to halogenophosphorus compounds, phosphorus esters (phosphinite, phosphonite and phosphites) and phosphorus amides (aminophosphines, phosphoramidites and diamidophosphites) are reported. Also a critical discussion, with an emphasis on their catalytic applications, is briefly assessed.

Crystal structure of (R)-2′-benz­yloxy-[1,1′-binaphthalen]-2-yl tri­fluoro­methane­sulfonate

In the title compound, C28H19F3O4S, a new 2′-benzyloxy (R)-BINOL derivative containing a trifluoromethanesulfonate group in the 2-position, the planes of the two naphthyl ring systems (r.m.s. deviations = 0.012 and 0.019 Å) are at an angle of 73.36 (2)°, and the planes of the benzyl ring and the naphthyl ring system bound to the ether O atom are at an angle of 75.67 (4)°. In the crystal, molecules are linked via C—H⋯F hydrogen bonds, forming chains propagating along [100]. The chains are linked via a weak C—F⋯π interaction and weak π–π interactions [shortest inter-centroid distance = 3.9158 (12) Å], forming a three-dimensional structure. The absolute structure of the molecule in the crystal was determined by resonant scattering [Flack parameter = 0.02 (6)].

2,2′-Bis(meth­oxy­meth­oxy)-3-methyl-1,1′-binaphth­yl

The title compound, C25H24O4, a methoxymethyl (MOM) bis-protected BINOL derivative containing a methyl substituent in position 3, is a key intermediate for the synthesis of a great variety of chiral auxiliaries. The planes of the naphthyl aromatic rings are at an angle of 70.74 (3)°. There are no conventional hydrogen bonds binding the molecules.