Jacobsen epoxidation

Jacobsen epoxidation
Named after Eric N. Jacobsen
Reaction type Ring forming reaction
Identifiers
Organic Chemistry Portal jacobsen-katsuki-epoxidation
RSC ontology ID RXNO:0000686
Jacobsen's catalysts
R = Alkyl, O-alkyl, O-trialkyl
Best Jacobsen catalyst: R = tBu
Katsuki's catalysts
R1 = Aryl, substituted aryl
R2 = Aryl, Alkyl

The Jacobsen epoxidation, sometimes also referred to as Jacobsen-Katsuki epoxidation is a chemical reaction which allows enantioselective epoxidation of unfunctionalized alkyl- and aryl- substituted alkenes.[1][2][3] It is complementary to the Sharpless epoxidation (used to form epoxides from the double bond in allylic alcohols). The Jacobsen epoxidation gains its stereoselectivity from a C2 symmetric manganese(III) salen-like ligand, which is used in catalytic amounts. The manganese atom transfers an oxygen atom from chlorine bleach or similar oxidant. The reaction takes its name from its inventor, Eric Jacobsen, with Tsutomu Katsuki sometimes being included. Chiral-directing catalysts are useful to organic chemists trying to control the stereochemistry of biologically active compounds and develop enantiopure drugs.

Several improved procedures have been developed.[4][5][6]

A general reaction scheme follows:[7]

  1. ^ Zhang, W.; Loebach, J. L.; Wilson, S. R.; Jacobsen, E. N. (March 1990). "Enantioselective epoxidation of unfunctionalized olefins catalyzed by salen manganese complexes". Journal of the American Chemical Society. 112 (7): 2801–2803. doi:10.1021/ja00163a052.
  2. ^ Jacobsen, Eric N.; Zhang, Wei; Muci, Alexander R.; Ecker, James R.; Deng, Li (1991). "Highly enantioselective epoxidation catalysts derived from 1,2-diaminocyclohexane". Journal of the American Chemical Society. 113 (18): 7063. doi:10.1021/ja00018a068.
  3. ^ Irie, R.; Noda, K.; Ito, Y.; Matsumoto, N.; Katsuki, T. (1991). "Catalytic asymmetric epoxidation of unfunctionalized olefins using chiral (salen)manganese(III) complexes". Tetrahedron: Asymmetry. 2 (7): 481–494. doi:10.1016/S0957-4166(00)86102-9.
  4. ^ E. N. Jacobsen; Deng, L.; Furukawa, Y.; Martínez, L. E. (1994). "Enantioselective Catalytic Epoxidation of Cinnamate Esters". Tetrahedron. 50 (15): 4323–4334. doi:10.1016/S0040-4020(01)89369-8.
  5. ^ Chang, S.; Galvin, J. M.; E. N. Jacobsen (1994). "Effect of Chiral Quaternary Ammonium Salts on (salen)Mn-Catalyzed Epoxidation of Cis-Olefins. A Highly Enantioselective, Catalytic Route to Trans-Epoxides". J. Am. Chem. Soc. 116 (15): 6937–6938. doi:10.1021/ja00094a059.
  6. ^ Brandes, B. D.; Jacobsen, E. N. (1994). "Highly Enantioselective, Catalytic Epoxidation of Trisubstituted Olefins". J. Org. Chem. 59 (16): 4378–4380. doi:10.1021/jo00095a009.
  7. ^ "Jacobsen Epoxidation". Organic Chemistry Portal. Retrieved 2009-09-22.