ID_Oxidations_IV - P Wipf Chem 2320 1 9 Jacobsen-Katsuki...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 9. Jacobsen-Katsuki Epoxidations Jacobsen, JACS 1990 , 112 , 2801; JACS 1991 , 113 , 7063; Katsuki, THL 1990 , 31 , 7345. Based on Kochi’s achiral salen catalyst. Mcgarrigle, E. M.; Gilheany, D. G., "Chromium- and manganese-salen promoted epoxidation of alkenes." Chem. Rev. 2005 , 105 , 1563-1602. Application in process chemistry ( THL 1995 , 36 , 3993): The use of the co-catalyst P 3 NO allowed for a decreased charge of the Mn salen catalyst in the Jacobsen epoxidation. P 3 NO stabilized the catalyst, increased the rate, and transported bulk oxidant HOCl into the organic phase ( JOC 1997 , 62 , 2222). P. Wipf - Chem 2320 1 2/15/2006
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Mechanistic considerations (Linker, T. Angew. Chem. Int. Ed. Engl. 1997 , 36 , 2060). Preferred directions of attack of alkenes according to Jacobsen ( a ) and Katsuki ( b ): 3 possible mechanisms regarding the oxygen transfer to the double bond: Epoxidation of styrene derivatives leads to mixtures: Radical clock experiments give conflicting results: There is clear evidence for the formation of radical intermediates, however, manganooxetanes, for which there is electrospray MS evidence, can also play a part in the mechanism. The influence of reaction conditions has to be taken into account. P. Wipf - Chem 2320 2 2/15/2006
Background image of page 2
3 Nielsen, L. P. C.; Stevenson, C. P.; Blackmond, D. G.; Jacobsen, E. N., "Mechanistic investigation leads to a synthetic improvement in the hydrolytic kinetic resolution of terminal epoxides (HKR) ." J. Am. Chem. Soc. 2004 , 126 , 1360-1362. The (salen)-Co(III) complex
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 17

ID_Oxidations_IV - P Wipf Chem 2320 1 9 Jacobsen-Katsuki...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online