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I want to reduce an ester and an eneone in the presence of a terminal epoxide.

I read on here @jerepierre did an ester in the presence of an epoxide with DIBAL.

I know the DIBAL works for my ester, but am not sure if it will also open the epoxide; reports are conflicting.

Any advice on reagents or conditions to consider or references to read are greatly appreciated!

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  • $\begingroup$ You have set yourself a tricky selectivity problem. From what I can find in the literature, Dibal-H reduces some epoxides under some conditions, often dependent on what neighbouring groups are present for the Al to bind to. I can only suggest that you try the reaction on a small scale at low temperature with a strictly controlled amount of Dibal-H. If this fails then I can only suggest you reconfigure your synthesis to avoid such an issue. $\endgroup$ – Waylander Aug 28 '19 at 12:53
  • $\begingroup$ Thanks @Waylander! Subsequently I have found epoxide ring openings with DIBAL tend to be from 0 C to reflux. and a reference (2014, Comprehensive Organic Synthesis, 2nd Edition. Chapter 8.10 Reduction of Carboxylic Acids and their Derivatives to Alcohols,. Ethers, and Amines. GE Arnott) had an example of this; Davies, K. A., et al. (2011). "Oxygen-containing analogues of juvenile hormone III." Tetrahedron Letters 52(18): 2302-2305 $\endgroup$ – billyben Aug 29 '19 at 7:57
  • $\begingroup$ Example is from this paper; Davies, K. A., et al. (2011). "Oxygen-containing analogues of juvenile hormone III." Tetrahedron Letters 52(18): 2302-2305. Ester in diethyl ether at -78°C, d/w DIBAL, stir 1 hr. -40°C for 2.5 hr. Rochelle's salt workup. $\endgroup$ – billyben Aug 29 '19 at 8:05

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