Carbon-leaving group bond

Other workers have concluded that the transition state for the Menshutkin reaction is late with more nitrogen-alpha carbon bond formation than alpha carbon-leaving group bond rupture. For instance, Harris and coworkers51 found that the secondary alpha deuterium kinetic isotope effects (Table 8) decreased when a poorer nucleophile was used in the S v 2 reactions between 3,5-disubstituted pyridines and methyl iodide in 2-nitropropane at 25 °C (equation 38, Table 8). 

Inversion of configuration requires that the nucleophile adds electrons to die a orbital of die carbon-tridate bond from die side opposite diat bond. As required by die stereochemistry, formation of die bond from azide to carbon is concurrent widi cleavage of the carbon leaving group bond. 

Figure 6.5, require alignment of a carbon-hydrogen bond with an adjacent carbon-leaving group bond. Furthermore, as shown in Figure 6.5, the relationship between these bonds is critical for elimination to occur. Specifically, the relevant bonds must adopt a trans relationship within the same plane. This relationship is referred to as frares-periplanar. 

The SnI substitution reaction is a two-step process, a slow Dn step to break the carbon-leaving group bond forming a carbocation, followed by a fast An trapping of the carbocation to form the new bond. The Dn and An paths are just the reverse of each other. Carbocations have just three fates They can be trapped by a nucleophile as discussed in this section they can lose a proton to form the alkene (Section 4.3), or they can rearrange to another carbocation of equal or greater stability (Section 4.7). 

The oxidative addition of a carbon-leaving group bond to a low-valent transition-metal complex may play the same role as the binding to a Lewis basic directing group in order to trigger intramolecular C-H activation [2, 3]. Inspired by Dyker s C-H self-condensation of ort/jo-substituted aryl iodides under hgand-free conditions [79,80], Baudoin and co-workers reported in 2003 the palladium(0)-catalyzed... 

Metal Catalyst Carbon Leaving Group Bond Formed... 

The Sn2 reaction and the E2 reaction are also competitive processes. In the Sn2 reaction, a nucleophile attacks the substrate at the tear of a carbon—leaving group bond. In the E12 reaction, it is the adjacent hydrogen that is removed along with the leaving group (Rg. 7.74). 

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