Reactions of Manganese and Rhenium Vinylidene Complexes with Hydrophosphoryl Compounds

We studied the reactions of manganese and rhenium phenylvinylidenes Cp­(CO)2MCC­(H)­Ph (Mn1 M = Mn; Re1 M = Re) with HP­(O)­R2 (R = C6F5, Ph, and OEt) and HP­(S)­Ph2, which resulted in the selective formation of η2-E-phosphorylalkene complexes Cp­(CO)2M­{η2-E-H­[R2(O)­P]­CC­(H)­Ph} (Mn2, Re2 R = C6F5; Mn3, Re3 R = Ph; and Mn6, Re6 R = OEt) and Cp­(CO)2M­{η2-E-H­[Ph2(S)­P]­CC­(H)­Ph} (Mn5, Re5). The DFT/B3LYP­(6-31G*) analysis showed the model reactions of Mn1 with HP­(O)­Me2 and HP­(O) (OMe)2 to proceed via the initial transition state Cp­(CO)2{Ph­(H)­CC}­Mn···HO–PR2 (TS1) where the minor PA form HO–PR2 is hydrogen-bonded to the metal, followed by stereoselective (trans- to the phenyl group) addition of the PA phosphorus atom to the Cα-vinylidene atom, which defines both the rate of the process and the anti-Markovnikov structure of the reaction product. The reactions can proceed at a relatively low content of the reactive PA form.

本研究考察了环戊二烯基（cyclopentadienyl, Cp）二羰基合锰与铼的苯基乙烯亚基配合物Cp(CO)₂M=C=C(H)Ph（Mn1：M=Mn；Re1：M=Re）与次膦酸衍生物HP(O)R₂（R为五氟苯基C₆F₅、苯基Ph、乙氧基OEt）以及二苯基硫代膦HP(S)Ph₂的反应，结果可选择性生成η²-E型膦酰基烯烃配合物：Cp(CO)₂M{η²-E-H[R₂(O)P]C=C(H)Ph}（Mn2、Re2：R=C₆F₅；Mn3、Re3：R=Ph；Mn6、Re6：R=OEt）与Cp(CO)₂M{η²-E-H[Ph₂(S)P]C=C(H)Ph}（Mn5、Re5）。采用密度泛函理论（Density Functional Theory, DFT）/B3LYP（6-31G*基组）对模型反应进行分析，结果表明：Mn1分别与HP(O)Me₂和HP(O)(OMe)₂的反应经由初始过渡态（transition state, TS）Cp(CO)₂{Ph(H)C=C=}Mn···HO–PR₂（TS1）进行，该过渡态中少量存在的质子酸型膦物种HO–PR₂与金属中心形成氢键，随后膦原子相对于苯基为反式地立体选择性加成至乙烯亚基配体的α-碳原子，该步骤同时决定了反应速率与产物的反马氏加成结构（anti-Markovnikov structure）。该类反应可在反应性活性膦物种含量较低的条件下顺利进行。