K. Kellner

Optisch aktive N-phosphinomethylierte α-aminosäuren: synthese und anwendung als liganden in asymmetrischen hydrierungen mit rhodium-komplexen

Abstract α-Aminoacids, their esters and sodium salts may be transformed by a modified Mannich-reaction into N -phosphinomethyl or N,N -bis(phosphinomethyl) derivatives. The sodium or triethylammonium salts of the chiral bisphosphines l -()- N,N -bis(diphenylphosphinomethyl)-alanine and -valine may be used as ligands to form enantioselective hydrogenation catalysts with rhodium complexes. The highest optical yield achieved was 29%.

Rhodiumkomplexe der N,N-bis(diphenylphosphinomethyl)aminosäuren; darstellung und untersuchung ihrer aktivität in enantioselektiven hydrierungen

Abstract The reaction of N,N -bis(diphenylphosphinomethyl)amino acid derivatives with [Rh(dien)Cl] 2 yields six-membered chelate-rhodium complexes, which in hydrogenation reactions achieve optical yields of about 30% of α-acetamidocinnamic acid derivatives, independently of the amino acid used. The synthesis of the pre-catalysts and NMR studies of the in situ preparation show complex formation corresponding to the various solvents used. In polar solvents active catalysts are formed.

Organoarsen-verbindungen: XXXIII. Synthese und reaktionsverhalten der α-aminomethylphosphine und -arsine

Abstract α-Dialkylaminomethylphosphines and the corresponding arsines have been obtained by the following methods: (1) by direct Mannich reaction, (2) by reaction of secondary phosphines and arsines with bis(dimethylamino)methane, and (3) by reaction of methyleneammonium halides with secondary phosphines and arsines, silylphosphines and silylarsines, and alkali phosphides and alkali arsides, respectively. The compounds obtained show a similar reactivity as N,N-acetals. The aminomethyl group is transferred to H-acidic agents, the reaction with halides yields methylene ammonium halides and halophosphines or haloarsines, respectively. Reactivity towards methyl iodide is influenced by substituents at the phosphorus or arsenic atoms. In the case of the phosphorus compounds acetylphosphines are obtained by reaction with acetyl chloride, while the arsenic compounds add acetyl chloride to give ammonium salts.

Synthese und reaktionsverhalten von (dialkylaminomethyl)chlorsilanen und -stannanen

Abstract (Dialkylaminomethyl)chlorosilanes have been obtained by the reaction of trichlorosilane with bis(dimethylamino)methane. The corresponding stannanes have been prepared by the addition of methyleneimmonium halides to SnCl2. In the silicon compounds a covalent SiCH2N bond is observed, while the tin compounds have ionic structures. Reactions of the new compounds are described.

1,3-CARBANIONISCHE UMLAGERUNGEN SYNTHESE VON BIS(o-HYDROXYARYL)- PHOSPHORVERBINDUNGEN

Abstract Phosphonic acid bis(o-haloarylesters) as well as the corresponding phosphoric acid derivatives are reacted with sodium giving bis(o- hydroxyaryl)phosphinoxides and phosphonic acid esters or amides, resp. The primary metallation products undergo rapid 1,3-carbanionic rearrangements. Magnesium may also be used as metallating agent if activated by means of anthracen in THF.

ORGANOARSENVERBINDUNGEN: 39 SUBSTITUIERTE BENZYLPHOSPHINE UND -ARSINE ALS LEICHT ZUGÄNGLICHE BIDENTATE LIGANDEN

Abstract 2-Hydroxybenzylamine bzw. 2- und 4-Aminobenzylamine reagieren mit Diphenylphosphin bei hoheren Temperaturen zu hydroxy- bzw. aminosubstituierten Benzylphosphinen. Im Falle der Alkoxy- bzw. Dialkylaminobenzylamine versagt diese Reaktion. Nach Uberfuhrung der Benzylamine in ihre quarternaren Ammoniumsalze und nachfolgende Umsetzung mit Natriumdiphenylphosphid werden die entsprechenden Alkoxy- bzw. Dialkylaminobenzylphosphine erhalten. In analoger Weise sind-auch 2-Alkylmercaptobenzylphosphine zuganglich. Aufgrund der unterschiedlichen Reaktionsbedingungen wird ein Eliminierungs-Additions-Mechanismus bzw. ein Substitutions-mechanismus diskutiert. Nach beiden Reaktionswegen sind auch die Stickstoff- bzw. Sauerstoff-substituierten Benzylarsine erhaltlich. 3-Dimethylaminomethylindol reagiert mit sekundaren Phosphinen und Arsinen entsprechend dem vorgegebenen Mechanismus zu 3-Indolylmethylphosphinen und -arsinen. 2-Hydroxybenzylamines or 2- and 4-aminobenzylamines react with diphenylphosphine at higher ...

Zur reaktion von vinyl- und allylphosphonaten mit dihalocarbenen — dihalocyclopropyl- und dihalocyclopropylmethylphosphonate

Abstract 2,2-Dihalocyclopropyl phosphonates and 2,2-dihalocyclopropylmethyl phosphonates are obtained by reaction of vinyl or allyl phosphonates with dihalocarbenes generated under phase-transfer reaction conditions. For the reaction of vinyl phosphonates with dichlorocarbene specific conditions are required; otherwise 3,3,3-trichloropropyl phosphonate is produced by addition of the CCl 3 anion to the olefin.

Unsymmetrisch substitutierte N,N-bisphosphinomethyl- und N-phosphinomethyl-N-thiomethyl-α-aminosäuren

Abstract Unsymmetrically substituted chiral N , N -bis(phosphinomethyl)-α-amino acid derivatives are formed by interaction of N -phosphinomethylamino acids with secondary phosphines and formaldehyde. Nucleophilic cleavage of N -phosphinomethyloxazolidine carboxylic acids with secondary phosphines is another method to obtain unsymmetrically substituted chiral biphosphine derivatives.

Zur Reaktion von Chlorsilanen mit Dialkylphosphonaten

SummaryThe reaction of dichlorodiorganosilanes with dialkylphosphonates is described. Depending on the reaction conditions diorganosilyl-bis(O-alkylphosphonates)R2Si[OP(O)H(OR′)]2 and diorganosilylphoshonates [-R2Si-OP(O)HO-], respectively, are formed.Using this type of reaction, O-alkoxysilyl O′-alkylphosphonates can be obtained both by interaction of dialkylphosphonates with dichlorodialkoxysilanes or chlorodialkoxyalkylsilanes, respectively.

Diastereoselective Synthetic Ways to P-Aspartic Acid Derivatives

Abstract α-Amino β-phosphono propionic acid derivatives are formed by reaction of alkali metal or triorganosilyl derivatives of 4-(P-substituted methyl) 5-hydroxy oxazoles with 0- or N-nucleophiles. A high diastereoselectivity of the reaction is observed depending upon the reaction conditions. The source of stereoselectivity is a substrat and/or reagent chirality. The dominant effect of the phosphorus substituent in the sterochemical course is proposed.