Addition to carbon-heteroatom

L. Miginiac, Nucleophilic Addition to Carbon-Heteroatom Multiple Bonds O, S, N, P, in Handbook of Grignard Reagents (G. S. Silverman, P. E. Rakita, Eds.), Marcel Dekker Inc., New York, 1996, 361-372. 

Meerwein type arylations involving radical additions to carbon-heteroatom multiple bonds such as in isothiocyanates have been further extended to tandem reactions leading to heterocycles [117, 118]. 

The mechanistic picture is further simplified by the fact that free-radical additions to carbon-heteroatom double bonds are not as prevalent. In most cases, it... 

Reactivity factors in additions to carbon-heteroatom multiple bonds are similar to those for the tetrahedral mechanism of nucleophilic substitution. If A and/or B are electron-donating groups, rates are decreased. Electron-attracting substituents increase rates. This means that aldehydes are more reactive than ketones. Aryl groups are somewhat deactivating compared to alkyl, because of resonance that stabilizes the substrate molecule, but is lost on going to the intermediate ... 

Nucleophilic Addition to Carbon-Heteroatom Multiple Bonds O, S, N, P... 

Scheme 13. Intramolecular diyl additions to carbon-heteroatom bonds...

NUCLEOPHILIC ADDITION TO CARBON-HETEROATOM MULTIPLE BONDS... 

The presence of two leaving groups allows for the introduction of two different nucleophilic species. In addition to carbon, heteroatom nucleophiles have been used. A wide variety of heterocyclic derivatives are available when difunctional, nucleophilic compounds are treated with (1) (eq 5). The synthetic potential of all of these derivatives is as wide as organosilicon chemistry. ... 

While the list of protocols for conjugate addition of boron and silicon nucleophiles to various acceptors is long, methods for the enantioselective 1,2-addition to carbon-heteroatom double bonds are still rare. 

Addition to Carbon-Heteroatom Multiple Bonds. The behavior of r-BuLi in reactions with carbon-heteroatom r-bonds is relatively unremarkable and parallels that of other organolithium reagents. Even in cases where steric hindrance might be expected to lead to difficulties, product yields are reasonable. Thus, for example, tri-f-butylcarbinol (3-r-butyl-2,2,4,4-tetramethyl-3-pentanol) may be prepared by addition of r-BuLi to di-r-butyl ketone (2,2,4,4-tetramethyl-3-pentanone), although there is a significant amount of reduction in this case, and V-lithio-di-r-butylimines may be generated by addition of r-BuLi to r-butyl cyanide. ... 

In this chapter, we will be studying addition reactions to carbon-carbon multiple bonds this is the converse process of the eliminations that we studied in the previous chapter. Addition to carbon-heteroatom multiple bonds is coming up in Chapter 14. Nucleophiles, electrophiles, and radicals can all add across double bonds first, we will concentrate on electrophiles and radicals, as nucleophiles only add readily when the double bond bears a group (such as a carbonyl, nitro, or nitrile Chapter 17) capable of accepting electron density. Reactions with electrophiles or radicals add two moieties, atoms or groups, by a stepwise process the two atoms or groups are not added simultaneously. However, there is another class of reactions where the two new bonds are made simultaneously—these are called concerted reactions. 

Chapter 14 - Addition to Carbon-Heteroatom Doubie Bonds 605... 

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