Amines, allylic, carbanions alkylation

Addition of the nucleophile can take place by two sterically different pathways. In the first (path (a)), direct attack on the rj -allyl group occurs trans to palladium. This is by far the commoner route and is followed by stabilized carbanions such as CH(C02R)2, CH(C0R)2, PhCHCN and CgHg , and normally also with amines. Aryl and alkyl carbanions (e.g. R CuLi) or hydride however add initially to the metal centre and then migrate to the allyl group (path (b)). The stereochemistry of the product depends on which mechanism is followed (v.i.). 

Chelating alkenes such as allylic10 and homoallylic11 amines and sulfides underwent alkylation by a range of stabilized carbanions to produce stable cr-alkylpalladium(II) complexes. In these cases the regioselectivity was strictly governed by the inherent stability of a five (versus four or six) membered chelate cr-alkylpalladium complex, with allylic systems (Scheme 5) being alkylated at the more sub-... 

Alkylation of allylnitroalkanes.9 Cyclic allylic nitro compounds react with stabilized carbanions or amines in the presence of Pd(0) at the allylic position without allylic transposition. The reactive intermediate is presumably an allylpalladium(Il) species. 

The. V-alkylation of ephedrine is a convenient method for obtaining tertiary amines which are useful as catalysts, e.g., for enantioselective addition of zinc alkyls to carbonyl compounds (Section D. 1.3.1.4.), and as molybdenum complexes for enantioselective epoxidation of allylic alcohols (Section D.4.5.2.2.). As the lithium salts, they are used as chiral bases, and in the free form for the enantioselective protonation of enolates (Section D.2.I.). As auxiliaries, such tertiary amines were used for electrophilic amination (Section D.7.I.), and carbanionic reactions, e.g., Michael additions (Sections D. 1.5.2.1. and D.1.5.2.4.). For the introduction of simple jV-substituents (CH3, F.t, I-Pr, Pretc.), reductive amination of the corresponding carbonyl compounds with Raney nickel is the method of choice13. For /V-substituents containing further functional groups, e.g., 6 and 7, direct alkylations of ephedrine and pseudoephedrine have both been applied14,15. 

The same type of reaction is known starting from organic halides, the M-C bond of the catalytically active species that further undergoes CO insertion being now generated by oxidative addition of the RX substrate. The Pd° complexes catalyze the carbonylation of vinyl, aryl, benzyl and allyl halides (but not alkyl halides that have one or several (3 hydrogen atoms) in the presence of a nucleophile NuH and a base (NEts) or NuM. Various nucleophiles can be used alcohols, amines, H2 (NuH) and carbanions (NuM) ... 

---