Lars-Inge Olsson

Stereochemistry of the organocuprate reactions of two cis–trans isomeric allylic ethers

(S)-cis-4-(1-Ethoxyethoxy)pent-2-en-1-ol reacts with methylmagnesium iodide in the presence of CuI to give (S)-2-methylpent-3-en-1-ol in an overall trans substitution, whereas (S)-trans-4-(1-ethoxyethoxy)pent-2-en-1-ol gives rise to the (R)-enantiomer, also in a trans substitution.

Chiral allenes are racemised by organocuprates

The chiral allenes (1) and (2) are racemised in the presence of various organocuprates, or, in the case of the alcohol (2), by methylmagnesium iodide alone; the racemisations probably proceed via an anion radical.