Stereoselective Diboration of Spirocyclobutenes: A Platform for the Synthesis of Spirocycles with Orthogonal Exit Vectors

The diastereo‐ and enantioselective diboration of spirocyclobutenes provides a platform for the rapid preparation of a wide variety of chiral spirocyclic building blocks. The chemoselective functionalization of the carbon‐boron bond in the products, including a stereospecific sp 3 ‐sp 2 Suzuki–Miyaura cross‐coupling reaction, provides a powerful tool to control the directionality and the nature of the exit vectors in the spirocyclic framework.