Thermodynamically Favored Aldol Reaction of Propargyl or Allenyl Esters: Regioselective Synthesis of Carbinol Allenoates

Abstract

Retroaldol regains control: A countercation may exert an important effect in promoting thermodynamic control in the TBAF-mediated aldol reaction of propargyl or allenyl esters (or a mixture of both) to produce, under mild conditions, carbinol allenoates exclusively (see scheme; TBAF=tetra-n-butylammonium fluoride).