Indium‐Mediated Allenylation of Aldehydes and Its Application in Carbohydrate Chemistry: Efficient Synthesis of <scp>D</scp>‐Ribulose and 1‐Deoxy‐<scp>D</scp>‐ribulose

Abstract

Abstract A two‐step reaction sequence starting with the indium‐mediated allenylation of aldehydes with 4‐bromo‐2‐butyn‐1‐ols and subsequent ozonolysis of the resulting allenylic product was developed to generate a variety of dihydroxyacetone derivatives. The regioselectivity of the indium‐promoted C–C bond‐forming reaction can be manipulated through hydroxy protecting groups on 4‐bromo‐2‐butyn‐1‐ol, yielding either allenes or alkynes as preferred products. Compared to established protocols, the necessary amount of indium for this type of allenylation can be decreased by a factor of two to four. The versatility of this strategy was demonstrated in thestereoselective and straightforward synthesis of D ‐ribulose and 1‐deoxy‐ D ‐ribulose.