Compounds with Three‐Membered Rings Containing Boron

Three‐membered ring systems containing heavier main group elements and almost every combination of elements can now be prepared. The isolobal analogy between C + and B makes three‐membered rings containing boron especially interesting for both theoreticians and synthetic chemists. With the synthesis of oxadiborirane 1 by Paetzold et al. ( Angew. Chem. Int. Ed. Engl. 1992 , 31 , 1040) and boriranes 2 by Berndt et al. (see communication on p. 1384) the synthesis of a diborirane, namely a B 2 C three‐membered ring, appears within reach. The carbon atom in such a molecule is postulated to have a planar bonding geometry. R = t Bu and 2,3,5,6‐Me 4 C 6 H, X = N(SiMe 3 ) 2 , Cl, Me.