Alkoxy- and hydroxycyclization of enynes catalyzed by Pd(II) and Pt(II) catalysts*
Véronique Michelet1, Lise Charruault1, Serafino Gladiali2, and Jean-Pierre Genêt1
1Laboratoire de Synthèse Sélective Organique et Produits Naturels, ENSCP, 11 rue P. et M. Curie, F-75231 Paris Cédex 05, France; 2Dipartimento di Chimica, Università di Sassari, Via Vienna 2, 07100 Sassari, Italy
Abstract: The development of a novel reaction ideal in terms of atom economy was achieved. The scope of the reaction was evaluated in the presence of Pd and Pt catalysts. The first enantioselective Pt-promoted enyne carboalkoxycyclization was developed in up to 85 % stereoselectivity. This ideal atom-economical reaction afforded the corresponding functionalized five-membered carbo- and heterocycles in good to excellent yields. The use of silver salts combined with (R)-Ph-BINEPINE, a monophosphane atropisomeric ligand, was found to be the best-suited combination for moderate to high enantioselectivities on carbonated and nitrogenated substrates.
Keywords: platinum; cycloisomerization; asymmetric catalysis; palladium; atom economy.
*Pure Appl. Chem. 78, 197-523. An issue of reviews and research papers based on lectures presented at the 13th IUPAC International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis (OMCOS-13), Geneva, Switzerland, 17-21 July 2005.