Roberto Olivera

The amine exchange/biaryl coupling sequence: a direct entry to the phenanthro[9,10-d]heterocyclic framework

Abstract Novel phenanthro[9,10- d ]pyrimidines and phenanthro[9,10- d ][1,2]oxazoles are regioselectively prepared by the application of a straightforward synthetic pathway, starting from new o , o ′-dihalogenated and non-halogenated 4,5-diarylpyrimidines and 4,5-diarylisoxazoles, respectively, prepared via a tandem amine exchange/heterocyclization of diarylenaminones. A comparative study of biaryl coupling methodologies provides two highly efficient, complementary procedures to accomplish the final coupling step: an intramolecular Stille–Kelly stannylation/coupling of halogenated diarylpyrimidines and diarylisoxazoles, and a PIFA-mediated non-phenolic oxidative coupling of the corresponding non-halogenated substrates. In addition, other alternative approaches to the same target tetracyclic systems are also examined.

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

DIBENZO[bf]OXEPINES: SYNTHESES AND APPLICATIONS. A REVIEW

2 . Synthesis of Dibenzo[bfloxepines from a Preformed Central Core ............................ 307 3 . Synthesis of Dibenzo[bJoxepines by Formation of the C-0 Biaryl Ether Bond ....... 310 a ) Formation of the Dibenzoxepine Nucleus via the Ullmann-ether Reaction ................... 311 b) Formation of the Dibenzoxepine Nucleus via the Aromatic Nucleophilic Substitution ....................................................................................................................... 316 4 . Miscellaneous Synthetic Methods for the Preparation of Dibenzoxepines ................. 320 111 . CONCLUSIONS ................................................................................................................... 322 LIST OF ABBREVIATIONS .................................................................................................... 323 REFERENCES ............................................................................................................................ 325

Dibenzoxepino[4,5-d]pyrazoles: a facile approach via the Ullmann-ether reaction

Abstract The application of a synthetic sequence of amine-exchange/Ullmann-ether reaction to 1,2-diarylenaminoketones for the access to dibenzoxepino[4,5- d ]pyrazoles is reported. The reaction proceeds efficiently, permitting to incorporate a variety of substituents.

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 novel palladium intramolecular diaryl ether formation

Abstract This paper presents an efficient methodology for the preparation of dibenzoxepino[4,5- d ]pyrazoles using a novel intramolecular palladium catalyzed diaryl ether formation. The effect of different chelating ligand systems, along with the unusual coupling reaction of phenoxides with aryl iodides and non-activated aryl moieties are also reported.

A new general method for the synthesis of 4-hydroxylated 3-aryltetrahydroisoquinolines

Abstract 3-Aryl-4-hydroxytetrahydroisoquinolines have been prepared from deoxybenzoins. The nitrosation of the latter derivatives has been improved and the catalytic reduction of the obtained oximinoketones has been carried out with the help of ultrasounds. Heterocyclization to the isoquinoline moiety occurred on the unprotected 1,2-aminoalcohol to give stereoselectively the corresponding hydroxylated heterocycle with good yield.

3-Aryl-4-Isoquinolinone Derivatives An Efficient Oxidative Preparation

Abstract A comparative study of the oxidation of 3-aryl-4-hydroxytetrahydroisoquinolines has been carried out. A modification of the Jones conditions turn out to be the best methodology for the regioselective preparation of target 4-isoquinolinone derivatives.