Synthesis of oxetane/azetidine containing spirocycles via the 1,3-dipolar cycloaddition reaction

Silver catalyzed 1,3-dipolar cycloaddition reactions between methyl 2-(oxetane/azetidine-3 ylidene)acetate as dipolarophiles and imines derived from α-amino acid methyl esters, 2-aminomethyl pyridine, and 2-aminomethyl pyrazine afforded oxetane/azetidine containing spirocycles in 40–77% yield. The use of 3-oxetanone used as the carbonyl compound thermal 1,3-dipolar cycloaddition reactions with secondary α-amino acids or methyl esters resulted in oxetane spirocycles in 62–90% yield.