Photochemical reactions of transition metal organyl complexes with olefins, 21 - Photolysis of tricarbonyl(eta(5)-cyclohexadienyl)manganese in tetrahydrofuran, reactions with cumulated dienes

[Mn(eta(5)-C6H7)(CO)(3)] (1) forms highly reactive [Mn(eta(5)-C6H7)(CO)(2)( THF)] (2) upon UV irradiation in THF at 208 K. solvent complex 2 reacts bet ween 208 and 293 K with 1,1-disubstituted allenes C3H2RR' [R, R' = CH3, CH3 (A); CH3, C6H5 (B); C2H5, C6H5 (C); C6H5, C6H5 (D); OCH3, Si(CH3)(3) (E)] to four different types of complexes: The [5+2] cycloadduct [Mn(eta(3:2)-C9 H9RR')(CO)(3)] (3E), rearranged [5+2] cycloadducts [Mn(eta(3:2)-C9H9RR')(CO )(3)] (4B, 4C, 4D), 1:2 adducts [Mn(eta(3:2)-C12H11R2R'(2))(CO)(3)] (5A-5E) , and the 1:3 adduct [Mn{eta(3:2:2)-C15H13(CH3)(6)}(CO)(2)] (6A). The const itutions of the products were established by IR and NMR spectroscopy, as we ll as by C,H elemental analysis and mass spectrometry. The crystal and mole cular structure of 6A was determined by X-ray structure analysis. A formati on mechanism for the complexes is proposed.