Coordination zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Chemistry Reviews, 120 (1992) 193-208 Elsevier Science Publishers B.V.. Amsterdam 193 Tripodal polyphosphine ligands control selectivity of organometallic reactions Claudio Bianchini’, Andrea Meli, Maurizio Peruzzini, Francesco Vizza and Fabrizio Zanobini Istituto per lo Studio della Stereochimica ed Energetica dei Composti di Coordinazione, C.N.R., Via J. Nardi 39, Florence 50132 (Italy) (Received 15 August 1991) CONTENTS A. B. C. D. Introduction ................................................ 193 Catalytic reactions ............................................. 195 (i) .Chemoselective reduction of cc,)%unsaturated ketones to allylic alcohols .......... 195 (ii) Regioselective synthesis of (G)-enol esters from I-alkynes and carboxylic acids ...... 197 (iii) Stereoselective dimerization of I-alkynes to (Z)-butenynes .................. 199 Stoichiometric reactions .......................................... 201 (i) Disproportionation reactions of acyclic ketones to carboxylate ions and ethers ...... 201 (ii) Oxidation of primary alcohols to carboxylic acids ....................... 202 (iii) Functionalization reactions of ethyne ............................... 204 Conclusions ................................................. 206 Acknowledgments ............................................... 206 References .................................................... 207 A. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA INTRODUCTION The development of the field of organometallic chemistry is largely driven by the prospect of using metal complexes as catalysts for the selective transformation of organic compounds. Selectivity is needed to produce pure products in high yields. In fact, the formation of by-products not only impacts on the economics of a process but, most importantly, provides environmental constraints. Our work attempts to address the question of selectivity in the transformation of organic molecules by examining the use of transition metal complexes stabilized by tripodal polyphosphine ligands. Some of these ligands are shown in Chart 1. The coordination chemistry of polyphosphines has been investigated widely over the past three decades by several research groups, particularly by those led by Sacconi [l], Meek [2] and Venanzi [3]. It is now apparent that polyphosphine ligands exhibit several advantages over comparable monodentate phosphines, includ- ’ To whom correspondence should be addressed. OolO-8545/92/$15.00 0 1992 Elsevier Science Publishers B.V. All rights reserved.