Planar Tetracoordinate Carbon in Organoboron Compounds: ab initio Computational Study

Ab initio MP2(full)/6-311++G** calculations revealed that 1,2-diboraspiro[2.2]pent-4-ene ( 11 ) and two of its isomers 14 and 15 possess stable structures with planar tetracoordinate carbon. These compounds and some of their derivatives, 21 and 22 , can be regarded as the first computationally found organoboron compounds with the planar tetracoordinate carbon.