Carbonyl nickel-catalyzed reductive allylation

Nickel-Catalyzed Reductive Allylation of Carbonyl Compounds with 1,3-Dienes... 

Although nickel-catalyzed carbonylative Pauson-Khand cycloadditions have not been broadly developed, related doubly carbonylative cycloadditions involving allyl halides have been demonstrated as an entry to functionalized cyclopentenones. In recent catalytic versions, iron powder was used as the terminal reductant and dehalogenating agent (Scheme 3-38). [Caution Ni(CO)4, which could potentially be liberated in this reaction, is a highly toxic gas.]... 

Even though Ni(CO)4 is called liquid death, this nickel catalyst has been applied in carbonylation reactions [52]. The group of Ricart reported a nickel-catalyzed carbonylative cycloaddition of alkynes and aUyl hahdes to cyclopentanes. The desired products were obtained in high yields and with controlled stereoselectivity. Iron was used as a reductant. An extension of the reaction to new substrates led to the conclusion that, although the steric and electronic effects of the alkyne substituents are generally irrelevant in relation to the adducts and their yields, those of the allylic counterpart may have a significant influence on the outcome of the reaction. However, the presence of the amine moiety in the alkyne completely inhibited the reaction. The feasibility of a multicentered reaction was verified with a triacetylene, in which up to 12 bonds were created simultaneously and in good yield (Scheme 1.30). 

---