Cathodic Addition of Benzylidyne Trichloride to Ketones and Aldehydes

Article abstract of DOI:10.1246/bcsj.61.125

Ketones are converted to homologated enones 7a-g in good yields by cathodic addition of benzylidyne trichloride (1d).As intermediates α-Chlorooxiranes 6 are assumed, which rearrange via α-keto carbenium ions 9 to enones.The intermediacy of 9 is supported by the addition of 1d to norcamphor, where the products indicate equilibrating norbornyl cations as intermediates. α,β-Unsaturated ketones lead depending on steric shielding of the double bond to the cyclopropane 23 as 1,4-adduct or the enone 26 as 1,2-adduct.With aldehydes and 1d, α-chloro or βhydroxy ketones, the conversion products of 2-chlorooxiranes, are obtained.