Synthesis of Functionalized Tetrahydropyrans by a Tandem Ene reaction-Prins cyclization

Trabajo presentado en la XXVI Reunión Bienal de Química Orgánica de la Real Sociedad Española de Química, celebrada en Punta Umbría, Huelva (España) del 14 al 17 de junio de 2016.The Prins cyclization is one of the most powerful tool to obtained substituted tetrahydropyrans. Overall, this process builds up one carbon-carbon bond, one heteroatom (0,N)-carbon bond, one halogen-carbon bond, and a ring in a stereoselective and efficient manner. [1] This cyclization is based on the reaction between a homoallylic alcohol or derivatives with aldehydes catalyzed by Bronsted or Lewis acid. [2] In this work, we shall show the tandem ene reaction-Prins cyclization catalyzed by iron(lll) salts. In this process, we are able to generate the homoallylic alcohol >in situ> through an ene-reaction and, then further Prins cyclization that generates, only in one step, tetrasubstituted tetrahydropyrans (Scheme 1).We thank the Spanish MINECO, co-financed by the European Regional Development Fund (ERDF), CTQ 2014- 56362-C 2-1- P for financial support.Peer Reviewe