Intramolecular Haloetherification and Transannular Hydroxycyclization of Alkenes. A Synthetic Methodology to Obtain Polycyclic Ethers and Amines

Intramolecular haloetherification and transannular hydroxycyclization of alkenes is a synthetic methodology to obtain polycyclic ethers and amines in a regio- and stereoselective manner. The stereoelectronic effects controlling this selectivity are discussed. Also, the methodology based on [4+3]-cycloaddition followed by intramolecular haloetherification or transannular hydroxycyclization is described as a very useful tool to prepare the dioxa- and oxazatricyclic cores of several bioactive natural products, whose molecular scaffold is quite difficult to reach by other synthetic approaches.