Sergio Pascual

Palladium catalyzed arylation for the synthesis of polyarenes

We present the current understanding on the mechanism of palladium-catalyzed arylation, which involves a proton abstraction by the base. In addition, we present selected examples of the application of this reaction for the synthesis of large polyarenes to highlight the variety of catalysts and reaction conditions that are currently used.

Synthesis of Fluoroalkylated β-Aminophosphonates and Pyridines from Primary β-Enaminophosphonates

A simple and efficient stereoselective synthesis of fluorine containing beta-aminophosphonates by reduction of beta-enaminophosphonates is described. Reduction with sodium cyanborohydride in the presence of zinc chloride and the catalytic hydrogenation of beta-enaminophosphonates gives beta-aminophosphonates. beta-Enaminophosphonates are also used as intermediates for the regioselective synthesis of fluoroalkyl-substituted pyridines.

Synthesis of fluoranthenes by hydroarylation of alkynes catalyzed by gold(I) or gallium trichloride

Summary Electrophilic gold(I) catalyst 6 competes with GaCl3 as the catalyst of choice in the synthesis of fluoranthenes by intramolecular hydroarylation of alkynes. The potential of this catalyst for the preparation of polyarenes is illustrated by a synthesis of two functionalized decacyclenes in a one-pot transformation in which three C–C bonds are formed with high efficiency.

Phenyliodine(III)bis(trifluoroacetate) mediated synthesis of phenanthro[9, 10-d] fused isoxazoles and pyrimidines

Abstract A novel protocol for the PIFA mediated regioselective oxidative coupling of 4, 5-diaryl substituted isoxazoles and pyrimidines leading to new phenanthro[9, 10- d ]heterocyclic systems is reported. The oxidative coupling of diarylisoxazoles and diarylpyrimidines is accomplished in the presence of phenyliodine(III) bis(trifluoroacetate) providing a concise route to new phenanthro[9, 10- d ]fused heterocyclic systems. Download full-size image

A novel approach to phenanthro[9,10-d]pyrimidinesvia an intramolecular Stille-type biaryl coupling reaction

Abstract New 4,5- o , o -dihaloarylpyrimidines, readily obtained from the corresponding enaminoketones, are transformed into phenanthro[9,10- d ]pyrimidines by means of a high-yielding tandem stannylation/biaryl coupling procedure. Proof of the pyrimidine formation mechanism is also presented.

A simple route to novel 2,5-dihydro-1,5,2-diazaphosphinines from primary enamine phosphonates

A simple method for the preparation of phosphorus-containing pyrimidine analogues such as 4,6-disubstituted-2-ethoxy-2,5-dihydro-1,5,2-diazaphosphinine 2-oxides 5 from primary enamine phosphonates and nitriles is described. A similar strategy is used for the synthesis of the corresponding 4,6-difluorinated-1,5,2-diazaphosphinine 2-oxide derivatives 8.