Ruthenium-catalyzed (2 + 2) intramolecular cycloaddition of allenenes

Abstract

We report a ruthenium-catalyzed (2 + 2) intramolecular cycloaddition of allenes and alkenes. We have found that the use of the ruthenium complex RuH2Cl2(PiPr3)2, which has previously gone unnoticed in catalytic applications, is crucial for the observed reactivity. The reaction proceeds under mild conditions and is fully diastereoselective, providing a practical entry to a variety of bicyclo[3.2.0]heptane skeletons featuring cyclobutane rings. © 2011 American Chemical Society.This work was supported by the Spanish MICINN (Projects SAF2007-61015, SAF2010-20822-C02, CTQ2008-00810, and Consolider-Ingenio 2010 CSD2007-00006), CSIC, Xunta de Galicia (GRC2010/12, INCITE09 209 122 PR), Comunidad de Madrid (CCG08-CSIC/PPQ3548), Diputación General de Aragón (E35), the Marie Curie Foundation (PERG06-GA-2009- 256568), and the European Social Fund. M.G. thanks the Xunta de Galicia for a Parga Pondal Contract. A.C. thanks the CSIC for her JAE Grant.Peer Reviewe