Base‐Catalyzed Direct Aldolization of α‐Alkyl‐α‐Hydroxy Trialkyl Phosphonoacetates

Pass the P: Catalytic direct aldol addition of α-hydroxy trialkyl phosphonacetates to aldehydes affords α-hydroxy-β-phosphonyloxy ester products (see scheme). The fully substituted glycolate enolate intermediate is generated in situ under mild conditions by a [1,2] phosphonate–phosphate rearrangement. High enantioselectivity and dramatic enhancement of reaction diastereocontrol is realized by the application of chiral iminophosphorane catalysts.