The Ugi reaction between 1-benzodioxanylmethyl-4-piperidone (I), N-Boc-leucine (II), butylamine (III), and isonitrile-bound resin produces the diamide resin (IV). Removal of the N-Boc group of (IV), followed by cyclative cleavage of the deprotected amino amide resin (V), affords the target spiro diketopiperazine derivative.