Ene reaction of chloral with olefins catalysed by Lewis acids, and some applications in organic synthesis

Abstract

Chloral has been found to react with representative examples of mono-, 1,1-di-, and 1,2-di-alkylsubstituted ethylenes to afford ene adducts in synthetically useful yield, and under mild conditions, when a Lewis acid is employed in catalytic quantities to enhance the reaction rate; the usefulness of these reactions is demonstrated by various transformations of the 1-hydroxy-2,2,2-trichloroethyl unit.