Oxidative Cyclopropanol Opening by Cob(III)alamin

Starting from the cyclopropanol 2 , the isomeric cyclopropanol 4 and the β, γ‐unsasturated aldehydes 7 and 8 have been produced by a cobalamin‐dependant transformation. In traces, the two acetoxycyclopropanes 3 and 6 , the saturated aldehydes 5 and 11 and the β,γ‐unsaturated aldehyde 9 could be detected ( cf. Structural Formulae and Table ). Starting from 4 the same products in a rather similar distribution were obtained. The isomerization 2⇄4 as well as the transformations leading to 7,8 , and 9 are shown to be mediated by cob(III)alamin (1(III)) . The results are explained on the basis of rearranging Co‐complexes. The migrations might be driven by the electrophilic nature of the central Co(d 6 )‐atom.