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Chiral oxygen-containing heterocyclic compounds are of great interest for the development of pharmaceuticals. Monoterpenes and their derivatives are naturally abundant precursors of novel synthetic chiral oxygen-containing heterocyclic compounds. In this study, acid catalyzed reactions of salicylic aldehydes with (−)-8-acetoxy-6-hydroxymethyllimonene, readily accessible from α-pinene, leads to the formation of chiral polycyclic products of various structural types. Three of the six isolated chiral heterocyclic products obtained from salicylic aldehyde contain previously unknown polycyclic ring types. Having carried out the reaction in the presence of Brønsted or Lewis acids (Amberlyst 15, trifluoromethanesulfonic acid, trifluoroacetic acid and boron trifluoride etherate) or aluminosilicates (montmorillonite K10, halloysite nanotubes), we found that the nature of products depends on the catalyst as well as the reaction conditions (reaction time, reactant ratio, presence or absence of solvent). Detailed mechanistic insight on the complex cascade reactions for product formation is provided with extensive experimental and quantum mechanical computational studies.
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Synthesis of α‐Sulfonyl Ketones through a Salicylic Acid‐Catalyzed Multicomponent Reaction Involving Arylsulfonation and Oxidation
Abstract The direct synthesis of α‐sulfonyl ketones was accomplished by a multicomponent reaction of styrene derivatives, anilines,t‐butyl nitrite, 1,4‐diazabicyclo[2.2.2]octane‐sulfur dioxide (DABSO), and oxygen catalyzed by salicylic acid. The aryl radicals generated from aniline derivatives andt‐butyl nitrite under the catalysis of salicylic acid was sulfonylated by DABSO to generate the arylsulfonyl radicals, which reacted further with styrenes, and then oxidized by oxygen to give the title compounds. Under the optimized conditions, the title compounds were obtained in good yields at ambient temperature within 1.5–2 h.
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- Award ID(s):
- 1664278
- PAR ID:
- 10361019
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemistrySelect
- Volume:
- 6
- Issue:
- 47
- ISSN:
- 2365-6549
- Format(s):
- Medium: X Size: p. 13577-13581
- Size(s):
- p. 13577-13581
- Sponsoring Org:
- National Science Foundation
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