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Topic: cyclopentene to 1,5-pentadiol  (Read 8317 times)

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cyclopentene to 1,5-pentadiol
« on: September 08, 2004, 11:02:58 PM »
Can you oxidize cyclopentene into 1,5-pentadiol in one stage?

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Re:cyclopentene to 1,5-pentadiol
« Reply #1 on: September 09, 2004, 12:05:37 AM »
Ozonolysis with a reductive work-up (NaBH4) should do the trick.
« Last Edit: September 09, 2004, 12:06:59 AM by movies »

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Re:cyclopentene to 1,5-pentadiol
« Reply #2 on: September 09, 2004, 07:25:26 AM »
Yes, apparently this is what they mean. A one stage process that consists of two parts :) I just thought maybe there's some sort of magic reagent I've never heard about, some selenium astatide or something...

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Re:cyclopentene to 1,5-pentadiol
« Reply #3 on: September 09, 2004, 12:14:51 PM »
I don't know much selenium chemistry, so there might be something.

Ozonolysis is always a two stage process.  I think that the NaBH4 step is essentially just tossing in some NaBH4 when the ozone addition is done, so it's virtually a one step conversion.  The ozonolysis to give the aldehydes would use a Me2S workup, so it's not like you would avoid a step otherwise.

huoshiyong

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Re:cyclopentene to 1,5-pentadiol
« Reply #4 on: September 09, 2004, 10:03:44 PM »
with H2O2

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Re:cyclopentene to 1,5-pentadiol
« Reply #5 on: September 12, 2004, 10:36:40 PM »
H2O2 will not split up the cyclopentene molecule at the C=C bond (?). It will only lead to epoxidation.

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Re:cyclopentene to 1,5-pentadiol
« Reply #6 on: September 13, 2004, 01:51:02 AM »
How about Jone's Reagent? Or Using Cold Alkali KMnO4 ??
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Re:cyclopentene to 1,5-pentadiol
« Reply #7 on: September 13, 2004, 11:49:51 AM »
I don't think that Jones reagent will oxidize double bonds.  KMnO4 can dihydroxylate (sometimes even cleave to the aldehydes, but then will oxidize to the acid), but then you still have to do another step or two to open the ring and get the alcohols.

BTW, H2O2 is a poor epoxidizing agent for olefins.  It does, however, work well for epoxidizing enones.  For olefins, electrophilic epoxidizing agents are better (e.g. m-chloroperbenzoic acid).

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