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Pure Appl. Chem., 2011, Vol. 83, No. 3, pp. 495-506

Published online 2011-02-07

Development of transition-metal-catalyzed cycloaddition reactions leading to polycarbocyclic systems

Moisés Gulías1, Fernando López2 and José L. Mascareñas1*

1 Department of Organic Chemistry, Center for Research in Biological Chemistry and Molecular Materials and Unidad Asociada to CSIC, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
2 Institute of General Organic Chemistry, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain

Abstract: We present a compilation of methodologies developed in our laboratories to assemble polycyclic structures containing small- and medium-sized cycles, relying on the use of transition-metal-catalyzed (TMC) cycloadditions. First, we discuss the use of alkylidenecyclopropanes (ACPs) as 3C-atom partners, in particular in their Pd-catalyzed (3 + 2) cycloadditions with alkynes, alkenes, and allenes, reactions that lead to cyclopentane-containing polycyclic products in excellent yields. Then, we present the expansion of this chemistry to a (4 + 3) annulation with conjugated dienes, and to inter- and intramolecular (3 + 2 + 2) cycloadditions using external alkenes as additional 2C-π-systems. These reactions allow the preparation of different types of polycyclic structures containing cycloheptene rings, the topology of the products depending on the use of Pd or Ni catalysts. Finally, we include our more recent discoveries on the development of (4 + 3) and (4 + 2) intramolecular cyclo-additions of allenes and dienes, promoted by Pt and Au catalysts, and discuss mechanistic insights supported by experimental and density functional theory (DFT) calculations. An enantioselective version of the (4 + 2) cycloaddition with phosphoramidite Au(I) catalysts is also presented.