Nickel Acetyl Acetonate [Ni(acac)₂]

Biographical Sketches

Ambuja Pande was born in 1979. She received her B.Sc. Chemistry (Honours) degree in (2000) and M.Sc. Organic Chemistry degree (2002) from Kurukshetra University, Kurukshetra, India. She joined the D.R.D.E. in 2002 as a JRF and is currently pursuing her Ph.D. under the guidance of Dr. R. C. Malhotra, Joint Director of DRDE. Her present research is focused on irritants, both synthesis and application aspects.

Introduction

Nickel acetyl acetonate is also known as bis(acetylacetonato) nickel(II ). It has been used as a catalyst for oligomerization, telomerization, hydrosilylation, reduction, cross-coupling, oxidation, conjugate addition, addition to multiple bonds and rearrangement reactions. It is a pale green solid (mp = 240 °C) that is soluble in ethers and ­aromatic and halogenated hydrocarbons.

Preparation

Ni(acac)₂ is commercially available. Alternatively, it can be prepared from potassium acetylacetonate and nickel(II ) chloride by stirring for 30 minutes at room temperature in absolute ethanol. [1]

Abstracts

(A) Ni(acac)2-catalyzed couplings of enones, alkynes and main-group organometallic reagents generate acyclic structures in an ­efficient manner. Ikeda et al. produced conjugated enynes from acetylenic tin reagents. [2] [3]
(B) Ni(acac)2 is used in InI-mediated direct allylation of carbonyl compounds with allylic alcohols. [4] The reaction proceeded smoothly with catalytic amounts of Ni(acac)2 and PPh3 to give the corresponding homoallylic alcohols in high yields. [5]
(C) Intermolecular coupling of an electron-deficient olefin with a strained olefin using Ni(acac)2 and a modified chiral monodentate oxazoline provides good yields and enantioselectivity. [6] [7]
(D) Ni(acac)2-catalyzed cross-coupling between two sp3 carbon centers allows the synthesis of polyfunctional products. [8]
(E) Ni(acac)2 promotes the coupling of alkenes with aldehydes in the presence of triethylborane or diethylzinc as reducing agents. [9] Triethylborane-mediated couplings work mainly for aromatic and unsaturated aldehydes, whereas diethylzinc-promoted couplings work best for aliphatic aldehydes and ketones. The reactions proceed well in water or in alcoholic solvents. [10]
(F) Ni(acac)2-assisted coupling of 1,7-diynes with silanes produces six-membered ring products with a Z-configured vinyl silane ­moiety. [11]
(G) Takimoto and Mori developed the Ni(acac)2-assisted coupling of 1,3-dienes, CO2, and an organozinc reagent, allowing easy assembly of densely functionalized rings. [12] Terao et al. developed comparable multi-component coupling of two dienes, a silyl ­chloride, and a Grignard reagent. [13] The procedure has been ex­tended to asymmetric variants. [14]

References

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2b Ikeda S. Kondo K. Sato Y. J. Org. Chem.  1996,  61:  8248 

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2d Ikeda S. Cui DM. Sato Y. J. Org. Chem.  1994,  59:  6877 

2e Cui DM. Tsuzuki T. Miyake K. Ikeda S. Sato Y. Tetrahedron  1998,  54:  1063 

3 Ikeda S. Kondo K. Sato Y. Chem. Lett.  1999,  1227 

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10 Kimura M. Ezoe A. Tanaka S. Tamaru Y. Angew. Chem. Int. Ed.  2001,  40:  3600 

11a Suginome M. Matsuda T. Ito Y. Organometallics  1998,  17:  5233 

11b Montgomery J. Angew. Chem. Int. Ed.  2004,  43:  3890 

12 Takimoto M. Mori M. J. Am. Chem. Soc.  2002,  124:  10008 

13 Terao J. Matsuo S. Shibata K. Tamaru Y. Angew. Chem. Int. Ed.  1999,  38:  3386 

14 Takimoto M. Nakamura Y. Kimura K. Mori M. J. Am. Chem. Soc.  2004,  126:  5956