- Metal-free, one-pot, sequential protocol for transforming ,-epoxy ketones to -hydroxy ketones and -methylene ketones
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A new sequential, one-pot protocol for transforming 1,3-disubstituted 2,3-epoxy ketones to β;-hydroxy ketones and α-methylene ketones has been developed. Reaction of epoxy ketones with boron trifluoride etherate (BF3·OEt2) generates the cationic intermediates by regioselective epoxide ring opening and an acyl shift. Then, a treatment of these cations with 2-aryl-1,3-dimethylbenzimidazolines (DMBIH) results in formation of 1,2-disubstituted 3-hydroxy ketones. DMBIH serves as a hydride donor in the second step of this process. Finally, the β;-hydroxy ketones can be converted to 1,2-disubstituted 2-methylene ketones by treatment with methanesulfonic acid or a combination of methanesulfonyl chloride and triethylamine. Importantly, the sequential steps involved in formation of the α-methylene ketone products can be carried out in one pot.
- Hasegawa, Eietsu,Arai, Saki,Tayama, Eiji,Iwamoto, Hajime
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p. 1593 - 1600
(2015/02/19)
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- Synthesis of phosphorylated enaminoketones and their application in the preparation of trifluoromethyl-functionalized 2-phosphonopyrroles
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New trifluoromethyl-functionalized 2-phosphonopyrroles were obtained by 5-exotrig cyclization of trifluoromethyl and phosphonyl functionalized enaminoketones. Copyright Taylor & Francis Group, LLC.
- Cal, Dariusz,Zagorski, Piotr
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experimental part
p. 2295 - 2302
(2012/04/10)
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- Highly chemo- and regioselective rearrangement of α,β-epoxy ketones to 1,3-dicarbonyl compounds in 5 mol dm-3 lithium perchlorate-diethyl ether medium
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Epoxides from α,β-unsaturated ketones undergo highly chemo- and regioselective rearrangement to 1,3-dicarbonyl compounds in 5 mol dm-3 lithium perchlorate-diethyl ether medium by a 1,2-migration of the carbonyl group at ambient conditions. The Royal Society of Chemistry 1999.
- Sankararaman,Ncsakumar
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p. 3173 - 3175
(2007/10/03)
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- Indium(III) chloride-promoted rearrangement of epoxides: A selective synthesis of substituted benzylic aldehydes and ketones
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A simple and efficient procedure for the rearrangement of substituted epoxides catalyzed by InCl3 has been developed. Aryl-substituted epoxides isomerize with complete regioselectivity to form a single carbonyl compound via cleavage of the benzylic C-O bond. The reactions are simple, fast, and high yielding. This procedure is very mild compared to those catalyzed with BF3 and other Lewis acids and compatible with several acid-sensitive functionalities. This protocol provides a highly selective synthesis of substituted benzylic aldehydes and ketones. However, rearrangement of alkyl- substituted epoxides is not very selective.
- Ranu, Brindaban C.,Jana, Umasish
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p. 8212 - 8216
(2007/10/03)
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