Synthesis of alkaline earth metallocenes from alkaline earth metal bis[bis(trimethylsilyl)amide] and 6-methyl-6-phenylfulvene

The transmetalation of bis[bis(trimethylsilyl)amino]stannylene in tetrahydrofuran with the alkaline earth metals yields the bis(tetrahydrofuran) adducts of calcium (la), strontium (Ib) and barium bis[bis(trimethylsilyl)amide] (1c). The metalation of 6-methyl-6-phenylfulvene with 1a, 1b and 1c gives 1,1'-bis(1-phenyl-ethen-1-yl)calcocene 2a, -strontocene 2b and -barocene 2c, respectively. The reaction of Ib with equimolar amounts of 6-methyl-6-phenylfulvene and acetophenone leads to the formation of bis[mu-[eta(5)-1-(3-hydroxy-1-methyl-1,3-diphenyl-2-propen-1-yl)-2,4-cyclo -pentadien-1-yl](2-)-C,O:O]tetrakis(tetrahydrofuran-O)distro ntium 3. The metathesis reaction of 2a with YCl3 and SnCl2 yields the corresponding yttrocenechloride 4 and stannocene 5. Crystallographic data of 1a: monoclinic, P2(1)/c, a = 841.6(4), b = 1936.9(6), c = 1938.0(10) pm, beta = 100.84(4)degrees, Z = 4, wR(2) = 0,1199); 1b: orthorhombic, Pbca, a = 1924.8(4), b = 1747.8(3), c = 1930.1(4) pm, Z = 8, wR(2) = 0.1248; 3: monoclinic, P2(1)/c, a = 1230.42(11), b = 1343.08(11), c = 1597.34(14) pm, beta = 104.610(7)degrees, Z = 4, wR(2) = 0.0980.