Oxidative Umpolung α‑Alkylation of Ketones

Szpilman et al. have reported [hydroxy(tosyloxy)iodo]benzene mediated the α-alkylative umpolung reaction of carbonyl compounds with dialkylzinc reagents. This reaction can be applied to a wide range of ketones, including 1,3-dicarbonyl compounds, leading to the corresponding α";"-alkylated carbonyl products in up to 93% yield. They have proposed a reaction mechanism from experimental and computational analysis which reaction proceeds through the umpolunged ketone enolate to α-electrophile by the action of the hypervalent iodine oxidant and subsequent addition of an alkyl nucleophile.

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TCI Mail No.157