Using t-Butylchlorodiphenylsilane

Alternatively, primary amines can be protected (2) as their mono-t-butyl-diphenylsilyl derivatives  

A solution of the primary amine (10 mmol), t-butylchlorodiphenylsilane (lOmmol), and triethylamine (15mmol) in MeCN (30ml) was stirred at ambient temperature for 1-3 h. The reaction mixture was concentrated in vacuo, and the residue was partitioned between hexane/AcOEt (4 1), and 1 m sodium hydrogen carbonate solution. The organic phase was dried over a mixture of potassium carbonate and sodium sulphate. 

Secondary amines do not react under these conditions. 

Secondary amines do not give the expected /V-TBDMS derivatives under the conditions normally used for similar alcohol protection (Chapter 14). Instead, iV-formamides are produced (3) in good yield through a DMF-derived Vilsmeier intermediate. 

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