Intramolecular arylation reactions of alkenes: a flexible approach to chromans and tetrahydroquinoline derivatives.

A metal-free approach to chroman derivatives by the reaction of different allylphenyl ethers with Ipy2BF4 is described. The access to this frame, by direct cyclization of the starting materials, takes place smoothly. In addition, an unusual and selective sequence that comprises initial rearrangement and further cyclization could be accomplished, with temperature as an excellent element of control. The process can be extended to the synthesis of tetrahydroquinolines when using allylamines. Also, two cascade reactions, leading to relevant oxygen and nitrogen-containing skeletons, have been devised.