Alkynyl cyanides, reactions with alkynes

Reaction with an amine, AIBN, CO and a tetraalkyltin catalyst also leads to an amide.Benzylic and allylic halides were converted to carboxylic acids electroca-talytically, with CO and a cobalt imine complex. Vinylic halides were similarly converted with CO and nickel cyanide, under phase-transfer conditions.Allylic (9-phosphates were converted to allylic amides with CO and ClTi=NTMS, in the presence of a palladium catalyst. Terminal alkynes were converted to the alkynyl ester using CO, PdBr2, CuBr2 in methanol and sodium bicarbonate. ... 

As with cyanide, Sn2 reactions of alkyne anions can be done with substrates other than halides or sulfonate esters. Epoxides are opened by acetylides at the less sterically hindered carbon to give an alkynyl alcohol. A synthetic example is the reaction of epoxide 38 with the indicated lithium alkyne anion gave an 85% yield of 39, an intermediate in the Sinha et al. synthesis of squamotacin.49... 

The scope of nitriles for the carbocyanation reaction of alkynes can be expanded by cooperative nickel/Lewis acid catalysis. Alkenyl [80, 81] and alkynyl cyanides [83, 84] also participate in the addition reaction to give highly conjugated nitrile products by nickel/BPh3 catalysis (Scheme 27). The use of aluminum-based Lewis acids causes isomerization of the double bond of alkenylcyanation products, whereas alkynylcyanation is sluggish with the aluminum reagents. 

Cyanogen iodide reacts with terminal alkynes forming alkynyl cyanides. The reaction is catalysed by CuOTf and 2,2,6,6-tetramethylpiperidine (TEMP) in yields between 45 and 78%. The first step in the reaction occurs when the alkyne reacts with I-CN and TEMP forming an alkynyl iodide. The product is formed when the alkynyl iodide reacts with a complex formed from CuOTf, TEMP, and a second molecule of I-CN. Many groups are tolerated in the terminal alkyne. 

The nickel-catalyzed carbocyanation of alkyne 74 with alkynyl cyanide 76 was accomplished using BPhg as the cocatalyst to produce 77. On the other hand, [2+2+2] trimerization of 74 predominated to form 78 when the reaction was conducted in the absence of BPhg (Scheme 6.15) [50]. An alkynylnickel complex formed via oxidative addition of BPhg-activated alkynyl cyanide has been identified. 

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