A C-F Bond Directed Diels-Alder Reaction.

We demonstrate a C-F bond driven Diels-Alder reaction of a fluorinated dienophile and a borole that shows remarkable diastereoselectivity. The product's structure was confirmed by X-ray crystallography, revealing an unusual conformation featuring a hypercoordinate boron. Calculations suggest that a B···F interaction instigates the reaction chemistry, the magnitude of which is maximized in the transition state-in essence, the B···F distance "yo-yos" from long to short in the transition state and back again to long in the product.