Methyl phosphite, nickel complexes

Methylation of aldehydes with trimethylaluminum is catalyzed by nickel complexes (Equation (80)).438 Phosphine or phosphite ligands considerably accelerate the reactions. 

C5H15O3P, Triethyl phosphite, iron complex, 26 61, 28 171 nickel complexes, 28 101, 104-106 CjHijP, Phosphine, triethyl-, gold-osmium complexes, 27 209, 211 gold-platinum complex, 27 218 nickel complex, 28 101 platinum complexes, 26 126, 135-140, 27 32, 34,28 27, 120, 122, 133, 29 191 C5H16N4, l,2-Ethanediamine,AfJVJV Af -tetramethyl-, lithium complex, 26 148 CjH,6P2, Phosphine, l,2-ethanediylbis(di-methyl-, nickel complex, 28 101 CjHijSi, Silane, triethyl-, ruthenium complex, 26 269... 

The nickel-catalyzed hydrocyanation of butadiene is a two-step process (Figure 3.32). In the first step, HCN is added to butadiene in the presence of a nickel-tetrakis(phosphite) complex. This gives the desired linear product, 3-pente-nenitrile (3PN), and an unwanted branched by-product, 2-methyl-3-butenenitrile (2M3BN). The products are separated by distillation, and the 2M3BN is then isomerized to 3PN. In the second step, 3PN is isomerized to 4PN (using the same nickel catalyst), followed by anti-Markovnikov HCN addition to the terminal double bond. The second step is further complicated by the fact that there is another isomerization product, CH3CH2CH=CHCN or 2PN, which is thermodynamically more stable than 4PN. In fact, the equilibrium ratio of 3PN/2PN/4PN is only 20 78 1.6. Fortunately, the reaction kinetics favor the formation of 4PN [95],... 

Industrial uses of HCN are for synthesis of methyl methacrylate and to form adiponitrile (for adipic acid and nylon) by addition to 1,3-butadiene in the presence of nickel(O) phosphite complexes. Waste HCN is also oxidatively hydrolyzed to give oxamide for use as fertilizer. 

---