Boron-Boron Dehydrocoupling of Boranes Initiated by Reaction with Iodine

Derivatization of an especially electron-rich diborane

Starting with electron-rich ditriflato-diborane B₂(hpp)₂(OTf)₂ (hpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-α]pyrimidinate), novel symmetric and unsymmetric diboranes B₂(hpp)₂X₂ and B₂(hpp)₂XY with X,Y = Br, NCS, N₃ or OTf are synthesized by substitution reactions with S_N1 mechanisms. The stability of the unsymmetric diboranes with respect to dismutation equilibria is evaluated.

Neutral cyclic sp2-sp3 and sp3-sp3 diboranes from N,N'-dicyclohexylcarbodiimide insertion into 1,2-dichlorodiboranes(4)

We report the synthesis and structural characterization of new neutral cyclic sp2-sp3 and sp3-sp3 diboranes from the reaction of N,N'-dicyclohexylcarbodiimide with 1,2-dichlorodiboranes(4) at room temperature. The present study is the first example of an insertion reaction of carbodiimide into diborane(4).

trans-Selective Insertional Dihydroboration of a cis-Diborene: Synthesis of Linear sp3 -sp2 -sp3 -Triboranes and Subsequent Cationization

The reaction of aryl- and amino(dihydro)boranes with dibora[2]ferrocenophane 1 leads to the formation 1,3-trans-dihydrotriboranes by formal hydrogenation and insertion of a borylene unit into the B=B bond. The aryltriborane derivatives undergo reversible photoisomerization to the cis-1,2-μ-H-3-hydrotriboranes, while hydride abstraction affords cationic triboranes, which represent the first doubly base-stabilized B₃ H₄ ⁺ analogues.