Alkyne insertion, nickel catalysed

A wide range of substituted isoquinolines (93) have been synthesized via a highly efficient nickel-catalysed annulation of the r-butylimines of 2-iodobenzaldehydes (91) and various alkynes (92) examination of the regiochemistry of the reaction revealed the operation of two different alkyne insertion pathways.119... 

A nickel-catalysed alkyne insertion between the carbonyl carbon and the -carbon of the cyclobutanone was achieved by combining a ketone-alkyne coupling reaction with a /3-carbon elimination process (Scheme 79).121 The reaction uses cyclobutanones as a four-carbon unit and provides access to substituted cyclohexenones. 

A nickel-catalysed [4-1-2] cycloaddition of formamides with allgmes through double C-H activation as shown in Scheme 14.67 was also carried out in the presence of AlMes, forming dihydropyridones along with a,p-unsaturated amides as side products. The side products were formed via insertion of alkynes into the C(0)-H bond. Use of PtBus as a ligand is crucial for the success of the reaction. If an unsymmetrical internal all ne is used, a mixture of regioisomers of dihydropyridones was obtained. ... 

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