Refluxing an aldehyde 1 with benzotriazole and benzylcarbamate in the presence of a catalytic amount of p-TsOH gave the corresponding benzyloxycarbonylamino-1-(1-benzotriazolyl)alkane 2 in good yields. Compounds 2 treated with substituted tert-butyl acetates 3 using LDA as a base afford smoothly and under mild conditions the N-2-protected 3-aminoalkanoic esters 4.