Reactions of yttrium-carbon bonds with active hydrogen-containing molecules. A useful synthetic method for permethylyttrocene derivatives

Article abstract of DOI:10.1021/om00153a004

Reactions of the permethylyttrocene compounds Cp*₂YCH(SiMe₃)₂ (1) and Cp*₂YMe·THF (2) with a variety of active hydrogen-containing substrates are reported. With HCl the known complexes (Cp*₂YCl)₂ and Cp*₂YCl·THF are formed. Reaction with 2,4-pentadione gives Cp*₂Y(acac) (3). Alcoholysis of 1 in Et₂O gives alkoxides Cp*₂YOR·OEt₂ (4, R = Me; 5, R = Et; 6, R = i-Pr). In the reactions with α-alkynes alkynyl complexes Cp*₂YC≡CR·OEt₂ (7a, R = Me; 8, R = Ph; 9, R = SiMe₃) are formed. When 2 reacts with propyne, Cp*₂YC≡CMe·THF (7b) is isolated. Reaction of 1 with excess of α-alkynes in nonpolar solvents shows a regioselective, catalytic dimerization to 1-en-3-ynes. Both 1 and 2 metalate pyridines at the α-position to give Cp*₂Y(η²-NC₅H₄) (13) from 1 and Cp*₂Y(η²-NC₅H₄)·THF (14) and Cp*₂Y(η²-NC₅H₃,6-Me) (15) from 2. Thermolysis of 1 in mesitylene gives the complex Cp*₂YDMB¹ (16), which reacts with THF to form Cp*₂YDMB·THF (17). The hydrides (Cp*₂YH)₂ (18) and Cp*₂YH·THF (19) are synthesized by hydrogenolysis of 1 and 2, respectively. The hydride 19 is a catalyst in H/D exchange reactions betweer sp³-CH and sp²-CD bonds.