Direct Synthesis of Boron-Protected Alkenyl- and Alkylborons via Copper-Catalyzed Formal Hydroboration of Alkynes and Alkenes

Formal hydroboration of internal alkynes proceeds regio‐ and stereoselectively by the use of a diboron reagent masked with 1,8‐diaminonaphthalene (dan) in the presence of readily available [(Ph3P)3CuCl], leading to direct formation of diverse B‐protected alkenylborons in high yield. The B(dan) moiety can also be efficiently installed into the CC double bond of alkenes to afford the respective alkylborons. dan‐ned if you do: A convenient and potent method for forming CB(dan) bonds that depends on copper‐catalyzed formal hydroboration of alkynes and alkenes with a masked diboron reagent is described. dan=1,8‐diaminonaphthalene.