Übergangsmetallaktivierte organische Verbindungen, XXXVII. über eine neue Aldehyd‐und Ketonreaktion: Synthese und spektroskopische Untersuchung von α1‐Phosphonioalkoxy‐übergangsmetallkomplexen

Transition Metal‐Activated Organic Compounds, XXXVII [1] . — A Novel Reaction of Aldehydes and Ketones: Synthesis and Spectroscopic Investigation of α1‐Phosphonioalkoxy Transition Metal Complexes Herrn Professor Ulrich Schöllkopf zum 65. Geburtstag gewidmet. By treatment of aldehydes and ketones with one mole equivalent of a Lewis acid (TiCl 4 , NbCl 5 , TaCl 5 ) and one mole equivalent of PPh 3 , or in one case of Ph 2 PCH 2 CH 2 PPh 2 , the aldehyde derivates [R 1 CH(P + Ph 2 R 2 )–OMCl n ]Cl – ( 4–8 ; MTi, Nb, Ta; R 2 Ph or CH 2 CH 2 PPh 2 ) and the ketone derivatives [R 1 R 2 C(P + Ph 3 )–ONbCl 4 ]Cl – ( 9–10 ) were prepared. Complexes 4–10 were isolated as air‐and water‐sensitive solids. According to the NMR spectra some of the obtained aldehyde derivatives 4–8 exist in solution as a mixture of isomers or oligomers, whereas the ketone derivatives 9 and 10 form in solution an equilibrium with the free ketone and the complex NbCl 5 · PPh 3 . The chloride ion of 4–10 is perhaps coordinated to the metal.