Addition of two alkyl groups

The Addition of Two Alkyl Groups to an Alkyne Dialkyl-addition... 

Tetramerization of alkynes 5-52 Dimerization of dienes 5-53 Addition of two alkyl groups to an alkyne... 

This last example shows the addition of two alkyl groups to a dinitrile (pKa =11). Because the alkyl groups to be added are identical, they do not have to be added in sequence. Instead, the reaction is conducted by adding two equivalents of base and two equivalents of the alkylating agent, benzyl chloride, simultaneously ... 

Earlier it had been found that interaction without additional electrophile led to transfer of two alkyl groups and ring opening to enediols with specific... 

Moreover, since the cyclobutanones are very often made from the dichloroketene adducts to alkenes, it is noteworthy that Grignard reactions of a,a-dichlorocyclobutanones, such as 7,7-dichlorobicyclo[3.2.0]heptan-6-one with allyhnagnesium bromide, give cyciobutanois, i.e. 6-ai-lyl-7,7-dichlorobicyclo[3.2.0]heptan-6-ol (3) with an exojendo ratio of ca. 10 1 and with no interference of the two chloro-substituents on the high yields.64 However, addition of smaller alkyl groups such as ethylmagnesium bromide resulted in a decrease in the exojendo ratio to ca. 3.2.64... 

Silyl groups, which tend to increase lipid solubility, may be used as a substitute for alkyl branching in space-filling groups. Direct substitution of a silicon atom for a carbon atom increases the hydrophobic character of a compound, even without the addition of more alkyl groups. Table III lists the relative partition coefficients of two pairs of carbon and silicon compounds in octanol-water, a system used to approximate the lipid-water system within an organism. As may be seen from the table, the silicon compounds are two to five times more soluble in the octanol phase this effect falls off with an increasing number of carbon atoms in the parent structure (36). 

In their zerovalent compounds, all three metals (Ni, Pd, Pt) undergo oxidative addition of alkyl, aryl, and acyl halides. For palladium, in particular, such reactions are key steps in a wide range of catalytic reactions. Palladium(II) and platinum(II) complexes also add C—X bonds to generate Pd(IV) and Pt(IV) species. Since C—C or C—H bond formation by reductive elimination often occurs readily, a common reaction sequence involves C—X addition followed by coupling of two alkyl groups, or an alkyl and a hydride ligand. 

Conjugate Addition Reactions. - Two protocols for achieving the enantioselective conjugate addition of an alkyl group to an enone using a cuprate containing a chiral ligand have been reported. In one case the lithium amide (28) was used to prepare an amidocuprate... 

It is also possible to show that oxidative conpling is a form of oxidative addition. Indeed, if one writes the oxidative addition of each olefin to a metallacyclopropane followed by a single reductive elimination of two alkyl groups from the two metallacyclopropanes, the same result is obtained as show below ... 

These facts are perfectly matched with our above-mentioned desired requirements. In addition, alkyl zinc is known to be less basic and deprotonation of ketone-aniline 36 by zinc reagent is highly unlikely. However, one of the issues for this reaction was the requirement for two alkyl groups on the zinc metal since the product ends up as tetramer 61, where the zinc atom still has one alkyl group, recalling that our cyclopropylacetylene (37) is not easy to obtain. 

---