Cycloaddition nickel -catalyzed

Table 2 Nickel-catalyzed cycloaddition of C02 and asymmetrical diynes...

It may very well turn out that electrocyclic reactions with transition metal complexes containing metal carbon bonds actually proceed as a sequence of several discrete steps, involving mutual changes from a- to jr-bonding 221>. The steps of such reactions can be stereoelectronically controlled in accord with the Woodward-Hoffmann rules, as shown by recent SCCC—MO calculations of nickel catalyzed cycloaddition reactions 505,506) e.g. ... 

The enormous scope and utility of nickel-catalyzed cycloadditions can be traced to pioneering studies of Reppe, who reported in 1948 that nickel catalysts promote the cyclooligomerization of acetylene to cyclooctatetraene. Not only was this unprecedented transformation described, but also a remarkable level of mechanistic insight was articulated in this report. In particular, this report depicted the formation of a 9-membered metallacycle en route to formation of cyclooctatetraene (Scheme 3-19). 

Several distinct strategies have been devised for the assembly of five-membered rings by nickel-catalyzed cycloaddition. Studies from Noyori " and Binger " established that Ni(0) complexes effectively catalyze cycloaddition... 

As illustrated in the early achievements from Reppe on the cyclotetramerization of acetylene and from Wilke on the cyclodimerization and cyclotrimerization of butadienes, nickel-catalyzed cycloadditions possess considerable potential in the construction of medium ring systems. Pioneering studies by Wender have demonstrated many practical implications that have advanced the... 

Following the early developments in nickel-catalyzed cycloadditions and cross-coupling processes, continued sophistication has been demonstrated over the years, and recent developments have elevated these classes of transformations into robust and useful catalytic processes. The recent burst of activity in these areas can be attributed to a better appreciation of both ligand effects and mechanistic considerations. Additionally, recent developments in reductive couplings, carbonyl additions, and C-H and C-C functionalization processes have demonstrated new reactivity trends and have suggested many new directions for continued development. Based on the current trajectory and recent fundamental findings, one can expect increased use of the types of reactions described herein as well as the discovery of many types of entirely new processes. 

Matsubara and coworkers have recently developed a nickel-catalyzed cycloaddition of isatoic anhydrides with alkynes to afford 2,3-disubstituted indoles in good yields (Scheme 22.16). The cycloaddition reaction proceeds via a decarbonylation, decarboxylation, and alkyne insertion sequence [24]. 

Nakai, K., Kurahashi, T., Matsubara, S. (2011). Nickel-catalyzed cycloaddition of o-arylcarboxybenzonitriles and alkynes via cleavage of two carbon-carbon a bonds. Journal of the American Chemical Society, 133, 11066-11068. 

Scheme 19 A plausible mechanism for nickel-catalyzed cycloaddition via C-CN and acyl-Ar activation...

Kumar P, Zhang K, Louie J (2012) An expeditious route to eight-membered heterocycles by nickel-catalyzed cycloaddition low-temperature C sp -C sp bond cleavage. Angew Chem Int Ed 51(34) 8602-8606. doi 10.1002/anie.201203521... 

Scheme 12) (during the preparation of this manuscript, a new asymmetric reaction was reported [55]) [56]. A similar mechanism was proposed and benzobicyclo [2,2,2]octenone 63 was isolated in high yield (77-97%) and ee (80-93%). Thus far, this is a unique example of an intermolecularcarboacylatiOTi of alkenes via C-C bond activation. One year later, Louie and co-workers reported a nickel-catalyzed cycloaddition of 1,3-dienes with 3-azetidin(Mies and 3-oxetanones [57]. In their report, the combination of Ni(cod)2 and monodentate phosphine P(p-tolyl)3 was found to successfully couple 1,3-dienes and 3-azetidinones/3-oxetanones and afford eight-membered heterocycles in medium to good yield. It is interesting to note that only 2,3-substituted dienes were suitable substrates, primarily because of sterics (Scheme 13). 

Tekavec TN, Zuo G, Simon K, Louie J (2006) An in situ approach for nickel-catalyzed cycloaddition. J Org Chem 71 5834—5836... 

A nickel-catalyzed cycloaddition reaction of diketene with alkynes furnished phenylacetic acid derivatives (Scheme 7.36) [51]. Although the reaction mechanism is unclear, the C=C double bond of diketene seems to be cleaved to constitute the para-carbons (designated by black circles) of the benzene ring. 

The [2 -I- 2 -I- 2] cycloaddition reaction was used successMly in the synthesis of the sesquiterpene alkaloid illudinine (Scheme 2.6) [5], The terminal diyne 27 bearing a gm-dimethyl group in the backbone successfully undergoes a nickel-catalyzed cycloaddition reaction with protected homopropargyl amine 28 to afford cycloadduct 29. This intermediate (29) was converted successfully to the natural product illudinine 30 in five simple steps. 

Hoberg and Burkhardt discovered that alkynes and carbodiimide can be coupled to afford N-analogs of pyridones [24], A brief investigation of the substrate scope revealed that symmetric alkyl-alkyl (93) and aryl-aryl (94) alkynes can be coupled with diphenyl carbodiimide (Scheme 2.28). Regioselective formation of iminopyri-dine 95 was observed when phenylmethylacetylene was subjeeted to standard reaction conditions. To our knowledge, no further development in this area of nickel-catalyzed cycloaddition has been made. Also, a successful version of Ni-catalyzed cycloaddition of diyne and carbodiimides is yet to be reported. 

Hsieh and Cheng reported that naphthalene-based aromatics can be accessed by a nickel-catalyzed cycloaddition route [26]. In this reaction, diiodoarenes serve as... 

Nickel-catalyzed cycloadditions can be classified into three types according to the mode formation of the heteronickelacycle (Scheme 12.1) (1) [4-1-2] cycloaddition via heteronickelacycle formation by oxidative cycloaddition of the 1,3-heterodiene to Ni(0) (2) [2 -I- 2 -I- 2] cycloaddition via heteronickelacycle formation by simultaneous assembling of a carbon-heteroatom unsaturated bond, alkyne, and Ni(0) and... 

Silyl-substituted diazomethanes are regarded as a silylcarbene precursor or as a diazomethane equivalent, as they coordinate, after loss of nitrogen, to transition metals to generate metal-carbene complexes and participate in a variety of metal-catalyzed reactions and the silyl substituent is readily lost in many cases after the total transformation. For example, nickel-catalyzed cycloaddition reactions of dienynes proceed with incorporation of a silylmethyl group to give seven-membered carbocycles having an allylsilane functionality (Scheme 3-69). ... 

Scheme 3-69. Nickel-catalyzed cycloaddition of trimetyl(diazomethyl)silane with dienynes.

Inami T, Baba Y, Kurahashi T, Matsubara S. Nickel-catalyzed cycloadditions of thiophthalic anhydrides with alkynes. Org. Lett. 2011 13 1912-1915. 

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