However, the applicability of this method is limited to the availability of dialkylboranes. Direct hydroboration usually fails to stop at the dialkylborane state, generally proceeding to the trialkylborane stage. Only in the case of relatively hindered alkenes does direct hydroboration stop at the dialkylborane stage. Hence, Zweifel's synthesis of trans-alkenes and ketones has found limited application in organic synthesis. The second disadvantage ...