Paolo Righi

Three-component process for the synthesis of 2-amino-2-chromenes in aqueous media

Abstract The reaction of an aldehyde, malononitrile and a phenol in water at reflux in the presence of cetyltrimethylammonium chloride (CTACl) as catalyst affords a one-pot synthesis of 2-amino-2-chromenes.

Supported organic catalysts: synthesis of (E)-nitrostyrenes from nitroalkanes and aromatic aldehydes over propylamine supported on MCM-41 silica as a reusable catalyst

Abstract MCM-41-supported propylamine showed high catalytic efficiency in the nitroaldol condensation between nitroalkanes and aromatic aldehydes.

Remote Control of Axial Chirality: Aminocatalytic Desymmetrization of N-Arylmaleimides via Vinylogous Michael Addition

Remote control of the axial chirality of N-(2-t-butylphenyl)succinimides was realized via the vinylogous Michael addition of 3-substituted cyclohexenones to N-(2-t-butylphenyl)maleimides. 9-Amino(9-deoxy)epi-quinine promoted the enantioselective desymmetrization, leading to atropisomeric succinimides with two adjacent stereocenters.

Clay-Catalysed Solventless Synthesis of trans-Chalcones

trans-Chalcones have been obtained in good yields and selectivities following an environmentally friendly methodology by using montmorillonite KSF as a reusable heterogeneous catalyst.

Enantioselective α-Benzoyloxylation of Ketones Promoted by Primary Amine Catalyst

A mixture of 9-amino-(9-deoxy)epi-dihydroquinidine and salicylic acid was able to promote the direct reaction of various cyclohexanones with dibenzoyl peroxide, thus affording the corresponding protected α-hydroxy carbonyl compounds in high yield and enantioselectivity. Interestingly the same catalytic salt was found to be active when 1-indanones derivatives were directly employed in the reaction with dibenzoyl peroxide furnishing chiral 1-oxo-2,3-dihydro-1H-inden-2-yl benzoates in high yields and enantioselectivity. Furthermore their treatment with NaBH(4) gives easy access to the corresponding enantioenriched 1,2-diols in high yields and without any loss of stereoselectivity.

TBD-catalysed solventless synthesis of symmetrically N,N′-substituted ureas from primary amines and diethyl carbonate

Symmetrically N,N′-substituted ureas were obtained from primary amines in very good yields under solvent-less conditions using diethyl carbonate (DEC) as the carbonylation reagent and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the base catalyst. The products are precipitated directly from the reaction mixture after a volatile organic compound (VOC) free aqueous work-up. The catalyst can be recovered and reused.

MCM-41-TBD as a new, efficient, supported heterogeneous catalyst for the synthesis of thioureas

The preparation of thioureas, by reaction of carbon disulfide with primary amines, can be efficiently catalyzed, under heterogeneous conditions, by MCM-TBD as a new and reusable catalyst.

Practical preparation of bicyclo[3.2.0]hept-3-en-6-ones and its utilisation in stereoselective total synthesis of grandisol and lineatin via a versatile intermediate

Abstract New and efficient stereoselective total syntheses have been devised for racemic grandisol and lineatin, two important components of pheromonic blends. They are based on the utilisation of 1,4-dimethylbicyclo[3.2.0]hept-3-en-6-one as a pivotal intermediate. This compound, as well as other bicyclo[3.2.0]hept-3-en-6-ones, are now easily available by a practical bicyclization of the corresponding 3-hydroxy-6-alkenoic acids.

Resolution and EPC synthesis of both enantiomers of 2,5-Dimethylbicyclo[3.2.0]heptan-endo-2-ol, Key Intermediate in the Synthesis of Grandisol.

Abstract The pure enantiomers of 2,5-dimethylbicyclo[3.2.0]heptan- endo -2-ol, key intermediate in the synthesis of grandisol, have been conveniently prepared by optiucal resolution with (2S)-(-)- and (2R)-(+)-1-(4-toluenesulphonyl)pyroolidine-2-carboxylic acid chloride (NTP-Cl) as resolving agents, and by an EPC synthesis employing commercially available (3R)-(-)-and (3S)-(+)-linalool as chiral sources.

Organocatalytic atroposelective formal Diels-Alder desymmetrization of N-arylmaleimides.

The atroposelective desymmetrization of N-arylmaleimides was realized by means of a primary amine catalyzed Diels-Alder reaction of enones. The chiral axis as new element of chirality is generated under the remote control of the catalyst that selectively drives the formal Diels-Alder reaction through an exclusive stereochemical outcome.