This cycloaddition reaction involves sixteen electrons; hence, it must be suprafacial on one component and antarafacial on the other.  Thus, it must be a [14s + 2a] or a [14a + 2s] cycloaddition.  The heptafulvene molecule is large enough that its p-electron system can twist without introducing too much strain or without losing too much p-electron overlap; hence, the cycloaddition is a [14a + 2s] process.  In either case, the product has the following stereochemistry: