Eduardo Martínez de Marigorta

2H-Azirines as Synthetic Tools in Organic Chemistry

The versatility and the high synthetic potential including the asymmetric syntheses of 2H-azirines as valuable precursors for the preparation of a wide range of polyfunctional acyclic and cyclic compounds, is discussed.

PREPARATION, PROPERTIES AND SYNTHETIC APPLICATIONS OF 2H-AZIRINES A REVIEW

INTRODUCTION .............................................................................................................................. 221 I . STRUCTURAL PROPERTIES OF W-AZIRLNES .................................................................. 222 1 . Molecular Orbital Calculations and Geometry ..................................................................... 222 2 . Spectroscopic Properties .......................................................................................................... 223 a) Nuclear Magnetic Resonance Spectroscopy ......................................................................... 223

Aza-Wittig reaction of N-phosphorylalkyl phosphazenes with carbonyl compounds and phenylisocyanate. Synthesis of 4-amino-3-phosphoryl-2-azadienes and pyrazine-phosphonates

Abstract Simple and functionalized N -phosphorylalkyl imines and N -phosphorylalkyl- N ′-phenyl-carbodiimides are obtained by aza-Wittig reaction of phosphazenes derived from aminophosphonates with carbonyl compounds and phenyl isocyanate. The reaction with dimethylformamide diethyl acetal (DMF–DEA) of these functionalized imines leads to the synthesis of 4-amino-3-phosphoryl-2-azadienes. N -Phosphorylmethyl imine derived from benzaldehyde can be used for the preparation of substituted pyrrole-phosphonates, while acid treatment of 4-dimethylamino-3-diethylphosphoryl-1-phenyl-2-azadiene gives diethyl 5-diethylphosphorylpyrazin-2-ylphosphonate.

A convenient alternative route to β-aminoketones

Abstract Enaminones has been prepared and submitted to conjugate reduction with LAH and the system Al2O3/R2NH to give β-aminoketones. The latter tandem amination system has also been applied in the Mannich reaction, improving the synthesis of several new diaryl β-aminoketones. Besides, the sequential use of DMFDMA and LAH-CuI on deoxybenzoins furnishes a new route for the synthesis of enones.

Synthesis and Reactivity of Imines Derived from Bisphosphonates and 3-Phosphorylated 2-Aza-1,3-dienes

Abstract The synthesis and some reactions of imines derived from aminoalkylbisphosphonates and 2-aza-1,3-butadienes is described. Bisphosphonylalkylimino compounds are useful intermediates in the preparation of aminoalkylbisphosphonate derivatives by reduction of the imino linkage with sodium triacetoxyborohydride as well as in the synthesis of 2-aza-1,3-butadienes by an olefination reaction. The electrocyclization of phosphorylated 2-aza-1,3,5-trienes afforded substituted 2-phosphorylated pyridines.

Synthesis of 3-phosphorylated 2-aza-1,3-dienes from imines derived from bisphosphonates

Abstract A synthesis of 2-aza-1,3-butadienes 3 substituted with a phosphonate group in the 3-position is described. The key step is the olefination reaction of bisphosphonylalkyl imino compounds 2 , with aldehydes in the presence of base. Heterocyclisation of 2-azatrienes 5 afforded substituted 2-phosphorylated pyridines 6 .

On the preparation and structural determination of 3-arylisoquinolinones

Abstract Two new methods for the oxidation of 3-aryl-3,4-dihydroisoquinolinium salts to 3-arylisoquinolinones have been developed: the direct ferricyanide oxidation and the air-oxidation of 1-cyanoisoquinoline intermediates.

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.

Silyl-cupration of an acetylene followed by ring-formation

The acetylenes 1a–e undergo silyl-cupration followed by cyclisation, the acetylenes 1f–1h react with the silyl-cuprate reagent more rapidly at the alternative electrophilic site, and the acetylenes 1i, 1j and 17 give relatively low yields of cyclic products amongst others. Ring-formation is, unusually, a not particularly favourable pathway.