Figure 4: Scope of alkynes.

Reaction conditions: 0.25 mmol of 3,4-(methylenedioxy)aniline (1a) or 3,4-domethoxyaniline (1m), alkynes (0.275 mmol), [Rh(cod)Cl]2 (2.5 mol%), dppm (10 mol%), (HCHO)n (2.5 equiv.) and 250 μl of H2O were heated at 100 °C under closed viol for specified time and depicted yields are isolated yields (yields in parentheses are recovery of the starting material).