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Fringuelli F, Pizzo F, Vaccaro L. NaOH-catalyzed thiolysis of alpha,beta-epoxyketones in water. A key step in the synthesis of target molecules starting from alpha,beta-unsaturated ketones. J Org Chem. 2004;69(7):2315-21doi: 10.1021/jo035804m.
Fringuelli, F., Pizzo, F., & Vaccaro, L. (2004). NaOH-catalyzed thiolysis of alpha,beta-epoxyketones in water. A key step in the synthesis of target molecules starting from alpha,beta-unsaturated ketones. The Journal of organic chemistry, 69(7), 2315-21. https://doi.org/10.1021/jo035804m
Fringuelli, Francesco, et al. "NaOH-catalyzed thiolysis of alpha,beta-epoxyketones in water. A key step in the synthesis of target molecules starting from alpha,beta-unsaturated ketones." The Journal of organic chemistry vol. 69,7 (2004): 2315-21. doi: https://doi.org/10.1021/jo035804m
Fringuelli F, Pizzo F, Vaccaro L. NaOH-catalyzed thiolysis of alpha,beta-epoxyketones in water. A key step in the synthesis of target molecules starting from alpha,beta-unsaturated ketones. J Org Chem. 2004 Apr 02;69(7):2315-21. doi: 10.1021/jo035804m. PMID: 15049624.
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J Org Chem. 2004 Apr 02;69(7):2315-21. doi: 10.1021/jo035804m.

NaOH-catalyzed thiolysis of alpha,beta-epoxyketones in water. A key step in the synthesis of target molecules starting from alpha,beta-unsaturated ketones.

The Journal of organic chemistry

Francesco Fringuelli, Ferdinando Pizzo, Luigi Vaccaro

Affiliations

  1. Dipartimento di Chimica, Laboratorio di Chimica Organica, Università di Perugia, CEMIN Centro di Eccellenza Materiali INnovativi per applicazioni chimiche, fisiche e biomediche, Via Elce di Sotto, 8 I-06123, Perugia, Italia. [email protected]

PMID: 15049624 DOI: 10.1021/jo035804m

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.

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