(Borylmethyl)trimethylsilanes are important building blocks in organic synthesis displaying a unique reactivity. Yet, the synthesis of more advanced derivatives is limited by the advanced silicon intermediates required for their preparation. Herein, a one-pot synthesis of (borylmethyl)silanes is developed, sourced on available alkyl-, aryl-, alkoxy-, aryloxy-, and silyl-hydrosilane materials. The privileged reactivity of N-hydroxyphthalimidyl diazoacetate (NHPI-DA) in Si-H insertion and α-silyl redox-active esters in different decarboxylative borylation reactions are scrutinized.