ZACA reaction

The zirconium-catalyzed asymmetric carbo-alumination reaction (or ZACA reaction) was developed by Nobel laureate Ei-ichi Negishi.[1] It facilitates the chiral functionalization of alkenes using organoaluminium compounds under the influence of chiral bis-indenylzirconium catalysts (e.g. bearing chiral terpene residues,[2] as in (+)- or (−)-bis[(1-neomenthyl)indenyl]zirconium dichloride[3]). In a first step the alkene inserts into an Al-C bond of the reagent, forming a new chiral organoaluminium compound in which the aluminium atom occupies the lesser hindered position. This intermediate is usually oxidized by oxygen to form the corresponding chiral alcohol (cf. hydroboration–oxidation reaction). The reaction can also be applied to dienes, where the least sterically hindered double bond is attacked selectively.[4]

ZACA reaction
Reaction type transition metal catalyzed organometallic functionalization
Reaction
alkene
+
organoaluminum compound
+
chiralzirconium catalyst
+
oxygen (optional)
↓
chiral alcohol
+
aluminum oxide
Conditions
Typical solvents typically DCM

See also

References
  1. Ei-ichi Negishi, ARKIVOC, 2011 (viii) 34-53, http://www.arkat-usa.org/get-file/37396/ and references therein.
  2. Denis Y. Kondakov; Ei-ichi Negishi (1995). "Zirconium-catalyzed enantioselective methylalumination of monosubstituted alkenes". J. Am. Chem. Soc. 117 (43): 10771–10772. doi:10.1021/ja00148a031.
  3. Bo Liang (2007). Zirconium-catalyzed Asymmetric Carboalumination of Alkenes (ZACA reaction): Its development and application to the synthesis of deoxypolypropionates and other chiral compounds (Google Books excerpt) (Ph.D. thesis). Perdue University. p. 29. ISBN 978-0-549-50694-2.
  4. Ze Tan; Bo Liang; Shouquan Huo; Ji-cheng Shi; Ei-ichi Negishi (2006). "Zirconium-catalyzed asymmetric carboalumination (ZACA reaction) of 1,4-dienes". Tetrahedron: Asymmetry. 17 (4): 512–515. doi:10.1016/j.tetasy.2006.01.017.
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