Preparation, Reactivity, and Spectral Properties of 1,3-Dioxin Vinylogous Esters: Versatile β-Ketovinyl Cation Equivalents

Article abstract of DOI:10.1021/jo00253a024

A full account of the preparation, reactivity, and spectral properties of three 1,3-dioxin vinylogous esters (4-6) is presented.The synthetic approach of these versatile β-ketovinyl cation equivalents involves a BF3*Et2O-promoted Prins reaction between cyclic 1,3-diketones (i.e., 1,3-cyclopentanedione, 1,3-cyclohexanedione, and 1,3-cycloheptanedione) and either formaldehyde or trioxane.The reactions explored include reductive and alkylative 1,3-ketone transpositions, affording a variety of simple β-unsubstituted and β-substituted α-hydroxymethyl α,β-enones, alkylations with carbon electrophiles, and hydroxylations with oxygen electrophiles.