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Synthese kann dies auch für die homogene K ata lyse von Bedeutung sein [3]. Nachdem wir uns in vergangenen A rbeiten mit Rhodium-, Iridium-, Ruthenium-und Osmiumver bindungen mit raum erfüllenden Phosphinoethern und Phosphinoaminen als Liganden beschäftigt haben [4][5][6][7], ist die vorliegende Publikation der Synthese sterisch anspruchsvoller Phosphinoester R 2 P(C H 2 )" C 0 2 R ' und ihrer Rhodiumkomplexe gewidmet. Wir zeigen, daß Phosphinoester mit un terschiedlicher Kettenlänge (n -1 ,2 oder 3) ent weder aus Silylphosphanen und ct»-Chloralkylestern oder, radikalisch induziert, aus sekundären Phosphanen und Acrylsäureestern zugänglich sind und daß vor allem die V ertreter mit R = /Pr und n -1 hervorragende Ligandeigenschaften besit zen. Die thermische oder photochemische Isom e risierung von Alkin-zu Vinyliden-Rhodiumkomplexen verdient dabei besonderes Interesse.

Several routes for the preparation of ω-cyanoalkyldiorgano phosphines RR′P (CH2)nCHR″CN (R = CH3, C2H5, C3H7, i-C3H7, C4H9, i-C4H9, t -C4H9, C5H11, c-C5H9, c-C6H11 ; R′ = i-C3H7, t-C4H9, C6H5; R″ = H, Si(CH3)3; n = 1, 2, 3, 4) have been investigated: (1) reaction of lithium diorganophosphides with ω-chloroalkylnitriles, (2) quaternization of secondary phosphines with co-haloalkylnitriles followed by deprotonation of the resulting H -phosphonium halides with aqueous bases, (3) hydrophosphination of secondary phosphines with unsaturated nitriles, (4) reaction of trimethylsilyl phosphines with (y-chloroalkylnitriles followed by Me3SiCl-elimination, and (5) addition of acrylonitrile to trimethylsilyl phosphines. The reaction of 3-chloropropionitrile with trimethylsilyl phosphines leads to the formation of a mixture of the expected phosphine and the corresponding β-silylated derivative. A mechanistic interpretation of the last reaction is given. All new compounds were characterized by elemental analyses, IR and NMR spectra.

The (diorganophosphinopropyl)alkyl ethers 1-7 are prepared by hydrophosphination of allylalkyl ethers with secondary phosphines. The corresponding thioethers cannot be obtained in a pure state by the same route. The nucleophilic ring opening of thiirane with lithium dialkyl phosphides, followed by the reaction with ClSi(CH3)3 or Cl(CH2)2OCH3 produces the thioethers 8-12 and 16. The silylated thioethers 8, 10 and 12 react with CH3OH/H2O to give the phosphinoethyl thiols 13-15. All new compounds have been identified and characterized by elemental analyses, IR and NMR spectra.