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Lewis Base Catalyzed Synthesis of Sulfur Heterocycles via the C1-Pyridinium Enolate.

ABSTRACT: While the addition of C1-Lewis base enolates to carbonyls and related structures are well established, the related addition to thiocarbonyls compounds are unknown. Herein, we report a reaction cascade in which a C1-pyridinium enolate undergos addition to dithioesters, trithiocarbonates and xanthates. The reaction provides access to a range of dihydrothiophenes and dihydrothiopyrans (28-examples). Mechanistic investigations, including isolation of intermediates, electronic correlation, and kinetic isotope effect studies support the viability of an activated acid intermediate giving rise to the C1-pyridinium enolate which undergoes turnover limiting cyclization. Subsequent formation of a β-thiolactone regenerates the catalyst with loss of carbon oxysulfide providing the observed products.

SUBMITTER: Cromwell S

PROVIDER: S-EPMC9545057 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature

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Lewis Base Catalyzed Synthesis of Sulfur Heterocycles via the C1-Pyridinium Enolate.

Cromwell Simon S Sutio Randy R Zhang Changhe C Such Georgina K GK Lupton David W DW

Angewandte Chemie (International ed. in English) 20220711 33

While the addition of C1-Lewis base enolates to carbonyls and related structures are well established, the related addition to thiocarbonyls compounds are unknown. Herein, we report a reaction cascade in which a C1-pyridinium enolate undergos addition to dithioesters, trithiocarbonates and xanthates. The reaction provides access to a range of dihydrothiophenes and dihydrothiopyrans (28-examples). Mechanistic investigations, including isolation of intermediates, electronic correlation, and kineti ...[more]

PMID: 35718884

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