C. Couret

A new stable germaphosphene and some of its chemical properties

Abstract A new stable germaphosphene, the 2,2-dimesityl-1-(2,4,6-triipropylphenyl)germaphosphene ( 1 ), has been made. It reacts quantitatively with benzaldehyde and α-phenyl- N -tert-butylnitrone to afford, by [2+2]- and [2+3]-cycoloadditions, respectively, the correponding four- and five-membered heterocycles 10 and 13 . The conformations of these heterocycles are discussed. The reactions of 1 and 2,2-dimensityl-1-(2,4,6-tri-tert-butyphenyl) germaphosphene ( 2 ) with these reagents are compared.

Dibisyl(fluorenylidene)stannene: evidence of its formation

Abstract The dibisyl(flourenylidene)stannene 4 , obtained by dehydro-chlorination or -fluorination of the corresponding chloro- or fluoro-stannanes 5 and 6 by tert-butyllithium is an extremely air-sensitive compound. It has not been isolated, but identified by trapping reactions by lithio compound and water.

METALLA IVb-PHOSPHOLANNES I. Dimetalla-2,5 Phospholannes, Metalla-2 Diphospholannes-1,3 et Metalla-3 Diphospholannes-1,2

Abstract We present the synthesis of novel sila-, germa- and stanna-phospholanes: 2,5-dimetallaphospholanes, 2-metalla 1,3-diphospholanes and 3-metalla 1,2-diphospholanes. Preparation and characterization reactions of the first stable diphosphorus germylene are also described. Nous decrivons dans ce memoire la synthese de nouveaux sila- germa- et stannaphospholannes: dimetalla-2,5 phospholannes, metalla-2 diphospholannes-1,3 et metalla-3 diphospholannes-1,2. Nous exposons egalement la preparation et les reactions de caracterisation du premier germylene diphosphore stable.

Mecanisme et stereochimie des reactions d'addition de silyl- et germylphosphines a divers reactifs insatures

Abstract Many addition reactions on Si-P or Ge-P bonds of 1,2-dimethyl 1-diethylphosphinosila (or germa) cyclopentanes to unsaturated dipolar reagents (aldehydes, ketones, heterocumulenes, ethylenic esters and nitriles) have been carried out. These reactions, studied from mixtures of geometrical isomers (Z

Inversion at phosphorus in dimetalla-IVb-phospholanes and metalla-IVb-diphospholanes

Abstract Inversion at phosphorus in dimetalla-IVB-phospholanes, metalla-IVB-diphospholanes and in a diphosphanylgermylene has been studied by 1 H and 31 P dynamic NMR spectroscopy.

FROM SILYLPHOSPHANES AND 2-BENZAL-1-INDANONES TO NEW PHOSPHANES, PHOSPHANE OXIDES OR SULFIDES AND PHOSPHONIUM SALTS

Abstract Diethyl(trimethylsilyl)phosphane 1 reacts with the conjugated carbonyl moiety of 2-benzal-1-indanones 2–6 to afford exclusively 1,4-adducts 2a–6a. Subsequent oxydation or sulfuration of most of the adducts leads to the corresponding phosphane oxides or sulfides. Further hydrolysis or reaction with HCl involves the desilylation with the formation of new (thio)phosphorylated ketones or phosphonium salts.

From Silylphosphanes and Oxazolones to New Phosphorus Amido-Acids

Silylphosphanes 3 and 4 gave 1,4-additions with the O=C-C=C moiety of oxazolones 1a-e and 2a-f to afford the adducts 5–8. Oxidation or sulfuration of 5–8 followed by hydrolysis led to oxyphosphorus (or thiophosphorus) amido-acids 9–11 and 15, 19, 20 respectively. A great difference was observed in the behaviour of thiophosphane oxides 16 (R = Me) and 17(R = Ph) toward hydrolysis: 16 led directly to the amido-acid 19 by opening of the lactonic ring whereas, from 17, the heterocyclic intermediate 18 could be isolated.

Synthesis and Reactivity of New Germa- and Stannaphosphenes

Abstract New stable compounds with a germanium (or a tin)-phosphorus double bond have been prepared respectively by a one step reaction between a lithiophosphide and a difluorogermane, or by dehydrofluorination of the corresponding fluorostannyl-phosphine with tert-butyllithium. Various types of cycloadditions ([2+2], [2+3] and [2+4]) have been observed with aldehydes, nitrones and α-ethylenic aldehydes and ketones.

EVOLUTION CONFIGURATIONNELLE DU PHOSPHORE DANS DES REACTIONS METTANT EN JEU DES LIAISONS PHOSPHORE-SILICIUM OU PHOSPHORE-GERMANIUM. STEREOCHIMIE DE REACTIONS DE SUBSTITUTION ELECTROPHILE. II

Abstract Many electrophilic substitution reactions on P[sbnd]Si or P[sbnd]Ge bond of 2-methyl-l-trimethylsilyl (or germyl)-3-phospholenes (5,6) with unsaturated dipolar reagents (aldehydes, heterocumulenes, ethylenic esters and nitriles), protonic derivatives (methanol, benzylthiol, acetic and benzoic acids) and trimethyl-chlorogermane have been carried out. These reactions are regiospecific and stereospecific, and proceed in all cases via inversion of configuration at phosphorus.