Synthesis of new chiral phosphine–phosphites and diphosphites and their application in asymmetric hydroformylation

https://doi.org/10.1016/S1566-7367(01)00022-XGet rights and content

Abstract

A new chiral phosphine–phosphite and two strictly related diphosphites have been synthesised and tested in the asymmetric hydroformylation of styrene. The catalytic efficiency of the phosphine–phosphite appears distinctly higher than that of the two diphosphites; in particular, it furnishes 2-phenylpropanal with very high regioselectivity and enantioselectivity up to 40%.

Introduction

In the last years we have observed an impressive expansion of the research devoted to the development of new chiral phosphorus ligands such as phosphine–phosphites [1], [2], [3], [4], [5], [6], [7] and diphosphites [2], [8], [9]. These efforts are due to the failure of simple methods to accurately predict the catalytic efficiency of a new chiral ligand and to the urgency to find appropriate ligands for many reactions. A very challenging example is the asymmetric hydroformylation of olefins. In fact even the most efficient ligands so far tested do not warrant the high regio- and enantioselectivity required for practical applications.

In this paper we report the synthesis of the new phosphine–phosphite (S,R,R)-1 and diphosphites (R,R,R)-2, (S,R,R)-2 (Scheme 1) and some preliminary studies of their catalytic activity.

Section snippets

Results and discussion

(S,R,R)-1 was synthesised by reacting (R,R)-3 [8], [10] with (S)-4 [11]; analogously the diphosphite ligands (R,R,R)-2 and (S,R,R)-2 were prepared by treatment of (R,R)-3 with (R)- or (S)-5 [12], respectively. Analytical and spectroscopic data for the new ligands are reported in Section 3.

The catalytic activity of 1 and 2 was tested in the asymmetric hydroformylation of styrene (Scheme 2).

The catalysts were prepared in situ by mixing [Rh(acac)(CO)2], a widely used Rh(I) precursor, with the

Materials and instruments

All manipulations were carried out under inert atmosphere (argon). Analytical grade solvents were purified following standard methods described in the literature [14].

(R,R)-(+)-1,2-diphenyl-1,2-ethandiol [10], 1-chloro-1-phospha-(3R,4R)-3,4-diphenyl-2,5-dioxacyclopentane (R,R)-3 [8], (S)-(-)-2-(diphenylphosphino)-2-hydroxy-1,1-binaphthyl (S)-4 [11] and (S)- and (R)-1,1-binaphthalene-2,2-diol (S)- and (R)-4 [12] were prepared according to the literature.

1H- and 31P-NMR were obtained on a

Acknowledgements

This work was supported by the Italian C.N.R. Progetto Finalizzato “Beni Culturali” and MURST Ministero Università Ricerca Scientifica e Tecnologica.

References (16)

  • A Kless et al.

    Tetrahedron Asymm.

    (1996)
  • T Higashizima et al.

    Tetrahedron Lett.

    (1994)
  • K Nozaki et al.

    J. Am. Chem. Soc.

    (1997)
  • C. Claver, P.W.N.M. van Leeuwen, in: Rhodium catalysed hydroformylation, P.W.N.M. van Leeuwen, C. Claver (Eds.), Kluwer...
  • T Horiuchi et al.

    Organometallics

    (1997)
  • S Deerenberg et al.

    Organometallics

    (2000)
  • N Sakai et al.

    J. Am. Chem. Soc.

    (1993)
  • D.J Wink et al.

    Inorg. Chem.

    (1990)
There are more references available in the full text version of this article.

Cited by (19)

View all citing articles on Scopus
View full text