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NaOH-Catalyzed Thiolysis of α,β-Epoxyketones in Water. A Key Step in the Synthesis of Target Molecules Starting from α,β-Unsaturated Ketones
- Source :
- The Journal of Organic Chemistry. 69:2315-2321
- Publication Year :
- 2004
- Publisher :
- American Chemical Society (ACS), 2004.
-
Abstract
- NaOH (0.02-0.3 molar equiv) is an efficient catalyst for the thiolysis reactions of alpha,beta-epoxy ketones with alkyl and aryl thiols in water. Thiolysis of 3,4-epoxyheptan-2-one (1) with thiols 2a-d has been accomplished in mild conditions (30 degrees C and pH 6 or 9) with complete C-alpha-regioselectivity and anti-stereoselectivity, and the corresponding anti-beta-carbonyl-beta-hydroxysulfides 3a-d have been prepared in excellent yields (95-98%). Compounds 3a-d, depending on their nature and pH conditions, have undergone dehydration, C-3 epimerization reaction, and retroaldol condensation. Dehydration of anti-3a-d has been chemoselectively carried out by in situ acidic treatment at 70 degrees C, giving stereoselectively the related (Z)-vinyl sulfides 4 in 89-94% overall yields. Under NaOH-catalyzed thiolysis conditions, cyclic alpha,beta-epoxyketones 6-9 have shown C-alpha attack only and spontaneously dehydrated to furnish the corresponding vinyl sulfides in high yields (90-96%). The reactions of calchone oxide (10) with thiols 2b-d have exclusively resulted in the formation of beta-carbonylsulfides 10b-d (82-93% yield), coming from the nucleophilic attack at the alpha-position and retroaldol condensation. To highlight the synthetic utility of this procedure, one-pot multisteps preparation of vinyl sulfides 7b and 7c, vinyl sulfoxides 12 and 13, and 1,5,6,7-tetrahydro-4H-1,2,3-benzotriazol-4-one (14) starting from 2-cyclohexen-1-one (11) have also been reported.
- Subjects :
- chemistry.chemical_classification
Ketone
Aryl
Organic Chemistry
Oxide
Sulfoxide
General Medicine
medicine.disease
Condensation reaction
Medicinal chemistry
Chemical synthesis
Catalysis
chemistry.chemical_compound
chemistry
Thiolysis
medicine
Molecule
Organic chemistry
Epimer
Dehydration
Chemoselectivity
Alkyl
Subjects
Details
- ISSN :
- 15206904 and 00223263
- Volume :
- 69
- Database :
- OpenAIRE
- Journal :
- The Journal of Organic Chemistry
- Accession number :
- edsair.doi.dedup.....7f3d01cf09f6318c4b91f0956a5f602a