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Updated: Nov 4, 2025

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Aldehyde to Ketone Homologation Enabled by Improved Access to Thioalkyl Phosphonium Salts
Meghan Fragis1, Jackson L Deobald2, Srinivas Dharavath3
1Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada.
Abstract:
Phosphines were previously unusable as Pummerer-type nucleophiles due to competing redox chemistry with sulfoxides. Here we circumvent this problem to achieve a formal phosphine Pummerer reaction that offers thioalkyl phosphonium salts that, in turn, give rise to diverse vinyl sulfides via Wittig olefinations. Thirty vinyl sulfides are thus prepared from (alkylthioalkyl)triphenyl phosphonium salts and aldehydes. The hydrolysis of these vinyl sulfides offers an efficient and versatile two-step one-carbon homologation of aldehydes to ketones.
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