Timeline for What is the mechanism for this reaction?
Current License: CC BY-SA 4.0
19 events
| when toggle format | what | by | license | comment | |
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| S May 24, 2021 at 19:24 | history | bounty ended | S R Maiti | ||
| S May 24, 2021 at 19:24 | history | notice removed | S R Maiti | ||
| May 23, 2021 at 1:32 | history | edited | Mathew Mahindaratne |
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| May 23, 2021 at 1:29 | answer | added | Mathew Mahindaratne | timeline score: 6 | |
| May 21, 2021 at 5:36 | history | protected | andselisk♦ | ||
| May 21, 2021 at 0:02 | comment | added | anomeric |  This is from March 6th edition page 1610. Does this help? :) | |
| May 20, 2021 at 21:42 | answer | added | user213305 | timeline score: 0 | |
| May 20, 2021 at 20:49 | answer | added | anomeric | timeline score: -2 | |
| May 20, 2021 at 20:16 | comment | added | user55119 | Now that a bounty has been placed on this post and a reputable source for the answer is requested, I seriously suspect that one will not be found. Any version of the Lossen rearrangement requires activation of the oxygen into a viable leaving group before base can effect deprotonation and alpha-elimination can occur to form the isocyanate. If the methyl carbamate is the desired product, simply treat the the activated hydroxamic acid with MeONa/MeOH rather than aqueous base. | |
| S May 20, 2021 at 18:57 | history | bounty started | S R Maiti | ||
| S May 20, 2021 at 18:57 | history | notice added | S R Maiti | Authoritative reference needed | |
| Jul 1, 2019 at 13:59 | comment | added | Curt F. | Seems like methanol/methoxide nucleophilic attack on the isocyanate (instead of water/hydroxide) would lead to the carbamate. Not sure if that squares with the supposedly two-step reaction scheme though. | |
| May 23, 2019 at 0:46 | history | edited | Melanie Shebel | CC BY-SA 4.0 |
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| May 10, 2019 at 18:04 | comment | added | Waylander | My thoughts. I think you have to deprotonate the NH of the hydroxamic acid and lose OH- to give the isocyanate analogous to the mechanism of the Lossen that you have drawn. This is the only option that makes any kind of sense, and it is known that deprotonation of hydroxamic acids proceeds at NH rather than OH. | |
| May 10, 2019 at 6:00 | history | tweeted | twitter.com/StackChemistry/status/1126728732750667778 | ||
| May 9, 2019 at 21:16 | comment | added | user55119 | First deprotonate and then lose carboxylate. The remaining neutral species reranges to an isocyanate. In methanol the isocyanate forms the methyl ester of a carbamic acid. Compare the similarity of the Lossen and Hofmann rearrangements | |
| May 9, 2019 at 20:35 | history | edited | FullBridge | CC BY-SA 4.0 |
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| May 9, 2019 at 20:25 | history | edited | FullBridge | CC BY-SA 4.0 |
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| May 9, 2019 at 20:20 | history | asked | FullBridge | CC BY-SA 4.0 |
