Journal of Molecular Catalysis A: Chemical 180 (2002) 177–185 Synthesis and catalytic activity of new supported rhodium(I) complexes for the enantioselective hydrogenation of methyl-(Z)--N-acetamidocinnamate Piero Mastrorilli a,∗ , Antonino Rizzuti a , Giuseppe Romanazzi a , Gian Paolo Suranna a , Roberto Gobetto b , Cosimo Francesco Nobile a a Dipartimento di Ingegneria Civile ed Ambientale (DICA) del Politecnico di Bari-Sezione Chimica and Centro CNR–MISO (Metodologie Innovative in Sintesi Organiche), Via Orabona 4, I-70125 Bari, Italy b Dipartimento di Chimica Inorganica, Chimica Fisica e Chimica dei Materiali dell’Università degli Studi di Torino, Via Pietro Giuria 7, 10125 Torino, Italy Received 15 June 2001; received in revised form 5 October 2001; accepted 12 October 2001 Abstract The polymerizable rhodium complex [(+)-diopRh(AAEMA)] (AAEMA - : deprotonated form of the ligand 2-(acetoace- toxy)-ethylmethacrylate) was obtained by reaction of (cod)Rh(AAEMA) with (+)-diop at -80 ◦ C. Supported chiral complexes have been obtained by copolymerization of [(+)-diopRh(AAEMA)] with N,N-dimethylacrylamide and N,N ′ -methylene- bisacrylamide or by reaction of [(+)-diopRhCl] 2 with an opportunely prepared poly(-ketoesterate). Catalytic tests carried out with the homogeneous catalyst or with both its heterogeneous analogues proved to be active in the enantioselective hydro- genation of methyl-(Z)--N-acetamidocinnamate yielding (S)-phenylalanine methylester with ee’s up to 67%. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Rhodium; Supported; Polymerizable complexes; Enantioselective catalysis 1. Introduction Due to their potential recyclability, much effort has been focused on supporting a metal complex exhibiting catalytic activity onto insoluble organic or inorganic matrices [1,2]. Catalyst activity and selec- tivity have been optimized by changing the nature of the support, as well as that of the metal centre [3–5]. The materials obtained by suitably anchoring a soluble metal complex onto a polymeric material are often referred to as hybrid due to their halfway nature between homogeneous and heterogeneous, and have ∗ Corresponding author. Fax: +39-80-5460-611. E-mail address: p.mastrorilli@poliba.it (P. Mastrorilli). been developed with the aim of combining the advan- tages of homogeneous catalysis in terms of activity and selectivity with those of heterogeneous systems. The synthetic strategies mostly used to synthesize a supported metal complex have been reported in Scheme 1. Route ‘a’ envisages the polymerization of an opportunely prepared metal complex and has the ad- vantage of the possibility to check the catalytic activity in the homogeneous and heterogeneous phases. Route ‘b’ is the “classical” synthesis of a macromolecular ligand followed by the anchoring of a metal salt or complex. Among the most recent examples of supported rho- dium catalysts are: (i) Rh complexes on Na + –bentonite 1381-1169/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII:S1381-1169(01)00424-1