Methyl abstraction

Lewis acid employed. The methyl abstraction occurs using fHCgFsL to give associated ion pair 353, whereas the use of A1(C6Fs)3 effects electrophilic addition to the methylene carbon on the enamide ligand backbone to give zwitterionic complex 354. The ion-paired complexes 353 are inactive for ethylene polymerization, but the zwitterionic complex 354, the remotely activated complex, rapidly consumes ethylene to form polyethylene. 

Methyl abstraction of Cp2ZrMe2 with a trityl salt of a highly methylated carborane anion, [GPh [closo-HCBuMen], shown in Equation (47), leads to formation of the cationic complex 727 in which the methyl zirconocene cation is closely associated with the methylated carborane anion through the Zr(/x-CH3)B motif.562 The Zr- H3G interaction is maintained in solution, as shown by a change in chemical shift for the methyl group... 

In Scheme 3, 29 is in nearly 1 1 equilibrium equilibrium with 30, formed by methyl abstraction by B(C6FS)3 to give the MeB(C6F5)3 counterion. This indicates that the electrophilicity of the [Re(CO)4(PR3)]+ fragment is similar to that of... 

In 1987 silylated biphenyl (101) was reacted with tribromoborane to suffer methyl abstraction and give the bromodimethylsilyl derivative (102) <87CB99l>. Heating (102) at 150°C causes cyclization to 5-dimethylsiladibenzoborole (103) (Scheme 17). Further reaction of (103) with tribromoborane yields 5-bromodibenzoborole (19). 

A simple mathematical model was formulated for the successive methyl abstraction hydrogenolysis mechanism illustrated in Figure 10. 

The feed molecule, n-Ci4, is used as a basis. It undergoes methyl abstraction to form methane and an n-Ci3 species... 

Some of the n-Cu species desorb from the catalyst and leave the system (fraction 1-a), the remainder (fraction a) undergoing further methyl abstraction to form additional methane and, as the co-product, n-Ci2 species etc. 

The extrusion of an alkene from a metal-alkyl (P-H elimination) explains the instability of metal-alkyl complexes having both NEV < 18 and at least one p-H atom, p methyl abstraction is also known, but only with early transition-metals and rare-earth complexes. 

Carre and co-workers studied a group of benzocycloalkenones that form tricylic benzocyclobutenols. As might be expected, transannular y-hydrogen abstraction competed with o-methyl abstraction only for ring sizes of 10 or more carbons, and again (O was nowhere near 0 . The cis geometry of the [4,n-i-l] bicycles formed is explained below. 

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