Synthesis of 2-Alkenyl-Tethered Anilines.

Three general routes for the synthesis of ( E )-2-alkenyl-tethered anilines have been developed. The first route involves a 3-aza-Cope rearrangement of N -allylic anilines in the presence of a Lewis acid. The requisite N -allylic anilines were prepared by the addition of vinyl-magnesium reagents to the corresponding aldimines. The second route details a direct cross-metathesis of 2-allylic or 2-homoallylic anilines with styrenes. The third route involves a palladium-catalyzed C-N cross-coupling of aryl halides. Taken together, these three strategies allowed access to the requisite aniline substrates with pendant alkenes at the 2-position with excellent trans selectivities.