Jean-Marc Denis

B(C6F5)3-catalyzed formation of B–P bonds by dehydrocoupling of phosphine–boranes

Tris(pentafluorophenyl)borane was used as a new catalyst in the formation of P-B bonds by dehydrocoupling of phosphine-boranes.

PH bond activation of primary phosphine-boranes: Access to α-hydroxy and α,α′-dihydroxyphosphine-borane adducts by uncatalyzed hydrophosphination of carbonyl derivatives

Abstract Primary P-phenyl and P-methyl phosphine-boranes 1 and 2 are prepared by complexation of the free phosphines with BH 3 · SMe 2 . They are stable and can be purified by distillation. Under basic conditions, they lead selectively to secondary alkylphosphine-boranes and under neutral conditions to the corresponding mono- and bis-hydroxyphosphine-boranes 5 and 6 . All these new compounds are purified by chromatography on silica gel. A competitive hydroboration induced by the decomplexation of BH 3 is observed as a minor process. Conditions for the decomplexation of phosphine-borane adducts are presented.

Synthese d'imines lineaires non-stabilisees par reactions gaz-solide sous vide(1)

Abstract Unstabilized inines are synthetized in gram-scale by vacuum dehydrochlorination of N-chloroalkylamines and by vacuum dehydrocyanation of α-aminonitriles on solid base. All the new compounds are characterized at low temperature by 1 H, 13 C NMR and IR spectroscopy.

Synthese d'imines cycliques non-stabilisees par reactions gaz-solide sous vide et thermolyse-eclair (1,2)

Abstract Unstabilized cyclic imines 1 – 4 were synthetized in gram-scale by vacuum dehydrochlorination of N-chlorocycloamines. Azirine 5 was prepared by flash vacuum thermolysis of the corresponding vinylazide 19 . All the new compounds were characterized at low temperature by 1 H, 13 C NMR and IR spectroscopy.

Preparative synthesis of primary vinylphosphines by chemoselective reduction of the corresponding vinylphosphonates

Abstract Primary vinylphosphines which were described as highly polymerisable compounds in the literature are prepared on gram scale in one step by a chemoselective reduction of the corresponding vinylphosphonates. They exhibit a surprising stability.

B(C6F5)3-catalyzed silylation versus reduction of phosphonic and phosphinic esters with hydrosilanes

Abstract HSiR3/cat-B(C6F)3 induced dealkylation or reduction of esters of phosphorus at 20°C. A specific conversion to silylesters occurred by reaction with tertiary silanes. In contrast, free phosphines were observed in the reaction with mono- or disubstituted silanes. A mechanism was proposed to rationalize these results.

Unhindered phosphaalkenes and phosphaalkynes in stable condition from a vacuum multistep sequence.

Abstract Unhindered low coordinated phosphines 5 - 6 are obtained in stable condition starting from dichlorophosphines 3 and 4 by a Flash Vacuum Thermolysis/Gas Solid Reaction sequence (FVT/GSR) and fully characterized by 1H, 13C and 31P NMR spectroscopy.

Hydrophosphination of α,β-unsaturated esters by primary phosphine-boranes; a useful entry to symmetrical and unsymmetrical phosphine-boranes

Abstract The reactivity of primary phosphine-boranes RPH 2 ·BH 3 (R = Ph and Me) towards CH 2 ue5fbCHCO 2 Me and CH 2 ue5fbCHP(O)(OMe) 2 is discussed. Hydrophosphination is the major process. The presence of the free phosphine (0–20%) in the crude media indicates that a competitive hydroboration reaction also occurs. The P ue5f8 H addition was found to be controllable to give, in reasonable yields, either the mono or the bis-adducts. All the adducts are stable and are fully characterized. The preparation of an unsymmetrical bis-adduct is also presented.

A Convenient Method for the Synthesis of α-Functionalized Chlorophosphonic Esters

Abstract α-Functionalized chlorophosphonic monoesters were easily prepared by a selective chlorination of the corresponding phosphonic diesters with phosphorus oxychloride.

First synthesis of secondary P-alkenyl and P-alkynyl phosphine oxides

A general method for preparing secondary P-alkenyl and P-alkynyl phosphine oxides, compounds unknown so far, involves the condensation of the vinyl Grignard reagent or lithium acetylide on P-chloroaminophosphines followed by acidic hydrolysis of the corresponding vinyl- or ethynylaminophosphines on a solid acid (Amberlyst 15). The few reported chemical properties are mainly related to the strong PH bond activation. Of special interest is the addition of a secondary vinylphosphine oxyde derivative on methyl acrylate which occurs at room temperature without any catalyst.