Nitriles alkynes

Synthesis of pure enantiomers. Brown and Singaram1 have reviewed the chiral organoboranes obtained from (+)- and (- )-pinene and their use for synthesis of optically pure amines, halides, hydrocarbons, lithium alkylborohydrides, ketones, aldehydes, a-chiral acids, esters, nitriles, alkynes, and alkenes. 

This index is provided so that the reader might locate information about a particular complex of interest. It is organized as follows The first section contains the neutral binary complexes, followed by charged dimers, and then by larger complexes in the last section. Within each section, the complexes are ordered by the type of molecules contained. The order is as follows XH, YH2, ZH3, carbonyl, carboxyl, imine, amide, nitrile, alkyne, alkene, alkane, others. (X refers to any halogen F, Cl, Br, I Y to O, S, etc. and Z to N, P, etc.) Any alkylated or similar substitutions follow immediately after their parent group. 

In contrast to carbocyclic alkyne cyclotrimerizations, the catalytic pyridine synthesis from alkynes and nitriles relies exclusively on cobalt catalysts with a few exceptions where rhodium [16] and iron complexes [17] could be applied. The cobalt-catalyzed pyridine synthesis can even be carried out in a one-potreac-tion generating the catalyst from C0CI2 6 H20/NaBH4 -1- nitrile/alkyne in situ [18]. 

Radicals generated at the cathode by either direct or indirect reduction (see also Section 2.6.5.2) have been added to alkenes, aromatic compounds, pyridinium salts, nitriles, alkynes, carbon and metals. 

The mechanism for this nitrile-alkyne co-oligomerization is assumed to be a catalytic cycle involving the metallacyclopentadienes 178 and 179 ... 

Accordingly, stable azazirconiacyclopentadienes 180 (formed from nitriles, alkynes and Cp2ZrEt2) react with alkynes in a Ni-catalyzed process to give pyridines 181 which formally result from cyclotrimerization of nitriles with two different alkynes [68]. 

Bu"C=CH and EtCN give mixture isomers. The catalyst is most active if Cp = C5H5 and L = C2H4 a variety of functional groups is tolerated. Nitrile alkyne ratios >5 suppress the formation of arenes. ... 

Terminal tungsten nitride complexes containing W N bonds have been reported to catalyze nitrile-alkyne cross-metathesis (NACM) by a mechanism that has parallels with the non-pairwise mechanism for olefin metathesis (A. M. Geyer, E. S. Weidner, J. B. Gary, R. L. Gdula, N. C. Kuhlmann, M. J. A. Johnson, B. D. Dunietz, J. W. Kampf, J. Am. Chem. Soc., 2008, 130, 8984.) When p-methoxybenzonitrile and 3-hexyne were mixed in the presence of catalyst candidate N=W(OC(Cp3)2Me)3(DME), two principal products attributable to metathesis were observed. 

Nitrile-Alkyne Cross Metathesis by the Reaction of W(N)Xj with 2-Butyne... 

Cohen SA, Bercaw JE (1985) Titanacycles derived from reductive coupling of nitriles, alkynes, acetaldehyde, and carbon dioxide with bis(pentamethylcyclopentadienyl)(ethyl-ene)-titanium(II). Organometallics 4 1006-1014... 

The cross-coupling of unactivated alkyl bromides and iodides with aryl(trimethoxy)silanes can be accomplished with PdBr2-P(f-Bu)2Me or air stable [HP(i-Bu)2Me]BF4-TBAF. Notably, the reactions occur under ambient conditions and with an array of compatible functional groups on the electrophile including ethers, acetals, nitriles, alkynes, esters, amides, and ketones (eq 41). Electron-rich and electron-deficient aryl(trimethoxy)silanes can be employed with the former providing higher yields. 

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