Migratory insertion reaction

Organometallic Compounds. Mononuclear carbon monoxide complexes of palladium are relatively uncommon because of palladium s high labihty, tendency to be reduced, and competing migratory insertion reactions in the presence of a Pd—C bond (201). A variety of multinuclear compounds... 

The migratory insertion reactions of the Ta-C functionalities in complexes 113-115 are presented in Scheme 22.9 In the reaction of 113-115 with both CO or Bu NC, the migration, under mild conditions (i.e., room temperature), of both alkyl or aryl groups to form r 2-ketones 116-118 and T 2-imino derivatives, 119-121, has been observed. Unlike the case of [Cp2M] or polyphenoxo derivatives of Ta, migration of the second alkyl or aryl group to the intermediate r 2-acyl or T 2-iminoacyl derivatives is very fast, which prevents the interception of the... 

The osmium hydroxycarbene complex 18 is formed in an acid-assisted migratory-insertion reaction of OsClEt(CO)2(PPh3)2. This alkyl compound results from reaction of the ethylene adduct 19 with one equivalent of acid 46). 

Dihalocarbene ligands, like other neutral 2-e donor carbon ligands, are expected to participate in migratory-insertion reactions when bound adjacent to a rx-bound alkyl or hydride ligand. An example is provided by the following reaction (119) ... 

Scheme 1.38. Migratory insertion reaction of alkynylzirconacyclopentene derivatives.

Scheme 1.40. Migratory insertion reactions of organyizirconocene derivatives with a- or y-haloorgano-lithiums.

CN Li-CH(Me) Cl Ph3Si LI-V7 Ll O Ph LjA-7 Ll O NC R1 uV ples of a-hetero-substituted or-ganolithiums used in migratory insertion reactions of organyizirconocene derivatives. 

Two mechanisms have been put forward, one involving P-hydride elimination and migratory insertion reactions, and the other one involving a direct, concerted transfer of the two hydrogen atoms from the alcohol donor to the reactive intermediate complex and vice versa donation to the ketone. Both pathways assume a heterolytic character for the overall transfer this is to say... 

Thus, the migratory CO insertion reaction on the iridium center, which is the rate-determining step of the iridium catalytic cycle, is accelerated by T ligand dissociation. These results tend to rationalize the seminal and inspired observations of Forster at Monsanto Co. [25]. 

Kinetic and Mechanistic Studies of Stoichiometric Reaction Steps 3.3.2.1 Migratory CO Insertion Reactions of Metal Alkyls... 

The main steps in the catalytic MeOH carbonylation cyde which were proposed for the Co catalysed process [2] have served, with some modification perhaps in the carbonylation of MeOAc to AC2O, to the present day and are familiar as a classic example of a metal catalysed reaction. These steps are shown in Eigure 5.1. They are of course, (i) the oxidative addition of Mel to a metal center to form a metal methyl species, (ii) the migratory insertion reaction which generates a metal acyl from the metal methyl and coordinated CO and (iii) reductive elimination or other evolution of the metal acyl spedes to products. Broadly, as will be discussed in more detail later, the other ligands in the metal environment are CO and iodide. To balance the overall chemistry a molecule of CO must also enter the cycle. 

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