Hydroboration‐Oxidation of 1‐Trialkylsilyl Dialkylphosphoramidopropynes. Regioselectivity and Reactivity.

Abstract The regioselectivity of the hydroboration of 1-trialkylsilyl dialkylphosphoramidopropynes was studied. The directive role of silicon was not always observed. In some cases inductive effects of substituents led to different and event opposite regioselectivity. We found here an interaction between boron and the phosphoryl group for the C2 addition which has not previously been observed. After oxidation, this interaction leads to byproducts. Understanding of the scope and limitations of this hydroboration-oxidation reaction enabled selective synthesis of the novel phosphorylated acids and ketones.