Palladium-Catalyzed Hydroboration/Cyclization of 1, n -Dienes.

While the hydroboration of alkenes is well established, the corresponding cyclization reaction of dienes remains challenging. Here, we report a new method for hydroboration/cyclization applicable to various 1, n -dienes and hydroboranes. The method features the direct synthesis of borylalkyl cyclopentanes from common 1,6-dienes, which is highlighted by syntheses of elaborated pyrrolidine cores from easily accessible diallylamines. Notably, 1, n -dienes ( n > 6) also undergo five-membered ring formation, offering "remote" hydroboration/cyclization that would be otherwise difficult to achieve.