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Chalcogenopyranones from disodium chalcogenide additions to 1,4‐pentadiyn‐3‐ones. The role of enol ethers as intermediates
Author(s) -
Leonard Kristi,
Nelen Marina,
Raghu Madhavi,
Detty Michael R.
Publication year - 1999
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570360322
Subject(s) - chemistry , sodium ethoxide , enol , ethanol , yield (engineering) , medicinal chemistry , organic chemistry , sulfide , sodium sulfide , alkyl , sodium , catalysis , materials science , metallurgy
Enol ethers 9 are formed as a mixture of E ‐ and Z ‐isomers from the addition of ethanol to 1,4‐pentadiyn‐3‐ones 2 in sodium ethoxide/ethanol. The enol ethers react with disodium chalcogenides to give the corresponding 2,6‐disubstituted chalcogenopyranones 1 bearing alkyl, aryl, or heteroaryl substituents in high yield as the only heterocyclic product of reaction. Diynones 2 react with disodium chalcogenides to give mixtures of products in which the chalcogenopyranones 1 are minor components and the dihydrochalcogenophenes 3 are the major products. The addition of hydrogen sulfide to diynone 2b in ethanol gives a product mixture nearly identical to that observed for the addition of disodium sulfide in sodium ethoxide in ethanol to 2b . Intermediates for the addition of hydrogen chalcogenides and disodium chalcogenides to both 2 and 9 are described, which lead to the heterocyclic products.