“Instant Methylide” Modification of the Corey–Chaykovsky Epoxide Synthesis

Abstract

We report that Me3S(O)+I− (1) and Me3S+I− (2) form stable, dry mixtures with KOt-Bu and NaH, respectively, which remain stable upon prolonged storage (>1 year). The corresponding methylides (Me2SO=CH2 and Me2S=CH2) are generated upon addition of DMSO or DMSO/THF solutions of carbonyl compounds, cleanly affording epoxides via the Corey–Chaykovsky reaction in good yields and short reaction times (as short as 20 min when 1–2 mmol of various ketones and aldehydes were treated with a mixture of 1 and KOt-Bu at 50–60°C).