Synthesis and crystal structure of 4,5-dibromo[2.1.1]triblattene

Reaction of 4-bromopentacyclo[7.3.0.0(2.7).0(3,11).0(6,10)]dodec-11-ene (1) With Br-2- CCl4 afforded 4,4,5 -tribromopentacyclo [7.3.0.0(2,7).0(3,11).0 (6,10)]dodecane (2) in 89-94% yield. Subsequent treatment of 2 with KOt-Bu- t-BuOH resulted in competitive elimination of the elements of HBr and of Br -2 with concomitant formation of 4,5-dibromopentacyclo[7.3.0.0(2,7).0(3,11) ,0(6,10)]dodec-11-ene (3, 76%) and 1 (17%), respectively. The structure of 3 was established unequivocally via application of X-ray crystallographic m ethods. Crystal data for 3: monoclinic, C2/c, a = 9.895(1), b = 9.0963(7), c = 12.471(1) Angstrom, beta = 106.875(8)degrees, z = 4.