Ligand-Accelerated Enantioselective Propargylation of Aldehydes

Significance

The value of homopropargylic alcohols is apparent from their frequent use during ­target synthesis. In addition these synthons are ­direct precursors to oxygen-containing hetero-­cycles. The authors describe a propargylation of aldehydes to access homopropargylic alcohols using propargyl iodides with stoichiometric loading of diethylzinc and a catalytic, proline-derived ligand. Similar methods to access homopropargylic alcohols exist (S. E. Denmark, T. Wynn J. Am. Chem. Soc. 2001, 123, 6199; D. R. Fandrick et al. J. Am. Chem. Soc. 2010, 132, 7600), but the current work stands out because the use of expensive ligands and toxic metals is avoided.