SYNTHESIS AND REACTIONS OF 1,1,2,2-TETRABORYLETHANE DERIVATIVES

Reaction of (Z)-1,2-bis(dichloroboryl)ethene with B2Cl4 leads to 1,1,2,2-tetrakis(dichloroboryl)ethane (1a) in 90% yield. Substitution of the chlorine atoms in 1a results in the formation of the iodo and amino derivatives 1b and 1c, d. Compound 1 b reacts with alkynes to give the 2,2'-linked 2,3-dihydro-1,3-diborole derivatives 2b, c which are aminated to yield 2d, e. Dehalogenation of 1d leads to the organoboron C2B4 cage 3d. The heterobicyclic compound 4d with two fused phosphadiborolane rings is obtained from ld and LiPH2. Reaction of 4d with (CO)3Fe(C8H14)2 gives the unusual diiron complex 5d. The constitutions of the new compounds are derived from spectroscopic data and are proven for 2e, 4d and 5d by X-ray structure analyses.