Pergamon Tetrahedron 55 (1999) 2103-2112 TETRAHEDRON Synthesis of Vinyl Nonaflates Derived from ~Ketoesters, [3-Diketones or ~-Diketones and Their Palladium-Catalyzed Cross-Coupling Reactions with Organozinc Halides Fabio Bellina,* Donatella Ciucci, Renzo Rossi* and Piergiorgio Vergamini Dipartimento di Chimica e Chimicalndustriale. University of Pisa, Via Risorgimento 35, 1-56126Pisa, Italy. a and Received 30 October 1998; revised 26 November 1998; accepted 17 December 1998 Abstract : Cyclic and acyclic ~-ketoesters4, a typicalcyclic ct-diketone 5 and a typical cyclic [~-diketone 6 were converted to the corresponding vinylnonaflates of generalformula 7, 8 and 9, respectively, by reactionwith 1.2-1.5 equiv of Nail in DMF at 20-55 °C followed by treatment with 1.15-1.30equiv of perfluoro-l-butanesulfonyl fluoride at 20 °C. These vinyl nonaflates,which were purified by MPLC on silica gel, proved to be excellent electrophiles in Pal-catalyzed cross-coupling reactionswith aryl-, l-alkynyl-and alkylzincchlorides. A varietyof cyclic and acyclic tetrasubstitutedc~,l~-unsaturated esters which includedstereoisomerically pure compounds,a 2- substituted 3-aryi-2-cyclopentenone and naturally-occurring dihydrojasmonewere cleanly synthesizedby these smooth and selectivecross-coupling reactions.© 1999ElsevierScienceLtd. All rightsreserved. In conjunction with our studies on the synthesis of biologically active natural compounds and their precursors by new procedures based on the use of transition metal-catalyzed reactions between organometallics and highly functionalized and stereodefined Csp2-electrophiles,1 recently we became interested in the synthesis of large amounts of highly functionalized substances, which are characterized by tetrasubstituted carbon-carbon double bonds, by palladium-catalyzed reactions of organometallics, which are tolerant of a variety of functional groups, and vinyl perfluoroalkanesulfonates such as those of general formula 1, 2 and 3. On the other hand, palladium-catalyzed cross-coupling reactions between organoboron, organoaluminum, organozinc or organotin compounds and vinyl triflates of general formula 1, 2 or 3 (where CnF2n+l = CF3SO2) have been extensively used in organic synthesis, 2-6 although these reactions, which sometimes are low yielding, do not appear to scale up owing to the high cost of triflic anhydride or N,N-bis(trifluoromethanesulfonyl)-N-phenylimide (N- phenyltriflimide), which are the reagents usually employed for the synthesis of compounds 1, 2 and 3 from the colTesponding 13-ketoesters 4, a-diketones 5 and I~-diketones 6, respectively.7-9 We now wish to report that vinyl nonaflates of general formula 7, 8 and 9 represent a convenient alternative to the triflates of general formula 1, 2 and 3, respectively. In fact, we found that compounds 7 and 9 can be efficiently prepared by reaction between the sodium enolates derived from compounds 4 and 6, respectively, and perfluoro-1- butanesulfonyl fluoride, an industrial reagent less expensive than triflic anhydride and, in particular, than N- 0040-4020/99/$ - see front matter © 1999 Elsevier Science Ltd. All rights reserved. PII: S0040-4020(98)01221-6