Dialkyl ethers, ROR´, are cleaved by hydrides (Cp* 2 LnH) 2 (Ln = Y 1a, La 1b, Ce 1c) to form alkoxides Cp* 2 LnOR (2), Cp* 2 LnOR´, R´H, and RH. The extent to which either of the C-O bonds of asymmetric substituted dialkyl ethers ROR´ is attacked strongly depends on the alkyl substituents but is relatively insensitive to the nature of the metal. Ring opening is observed with THF or 1,4-dioxane leading to Cp* 2 YO n Bu (6a) and (Cp* 2 Y) 2 (µ-OCH 2 CH 2 O)-(THF) 2 (8), respectively. The molecular structure of 8 was determined by X-ray diffraction. Space group Pbcn had unit cell parameters a = 21.7483 (12) Å, b = 14.2806(12) Å, c = 16.726(2) Å and Z = 4. Least-squares refinement based on 4163 reflections converged to R = 0.063. Unsaturated ethers, vinyl ethyl ether and allyl ethyl ether, are cleaved instantaneously by 1a to form Cp* 2 YOEt. Also, the C-O bonds of Cp* 2 LnOEt are attacked by (Cp* 2 LnH) 2 to give the oxo bridged compound (Cp* 2 Ln) 2 (µ-O) and ethane. The molecular structure of the THF adduct of the cerium analogue (Cp* 2 Ce) 2 (µ-O)(THF) 2 (12) was determined by X-ray diffraction: spacegroup P1 had unit cell parameters a = 13.399(2) Å, b = 14.864(4) Å, c = 15.812(6) Å, α = 70.75(2)°, β = 85.15(2)°, γ = 63.78(2)°, and Z = 2. Least-squares refinement based on 6294 reflections converged to R = 0.038. In contrast to ethers, organic sulfides RSRá re metallated by 1a to produce products Cp* 2 YCH 2 SMe (13, R = R´ = Me), Cp* 2 -YCH(SMe)Ph (15, R = Me, R´ = Ph), Cp* 2 Y(SC 4 H 3 ) (18, RR´ = CH=CHCH=CH), and dihydrogen. Only Et 2 S underwent C-S cleavage to form Cp* 2 YSEt (16) and ethane. Reaction of 1a with allyl methyl sulfide is not clean, but 1a is a modest catalyst for the hydrogenation of allyl methyl sulfide.
IntroductionOrganometallic compounds of group 3 and lanthanide metals are very active catalysts for polymerization 1 and hydrogenation 2 of olefins. Also, cyclization of 1,4-, 1,5-, and 1,6-dienes is very efficiently catalyzed by scandium and yttrium complexes. 3 However, in general, these catalytic processes have severe limitations, since they can only be performed with nonfunctionalized olefins. Lauke, H.; Mauermann, H.; Swepston, P. N.; Schumann, H.; Marks, T. J. Lauke, H.; Mauermann, H.; Schumann, H.; Marks. T. J. J. Am. Chem. Soc. 1985, 107, 8111. (b) Conticello, V. P.; Brard, L.; Giardello, M. A.; Tsuji, Y.; Sabat, M.; Stern, C. L.; Marks, T. J.
