Chemoselective three-component synthesis of -carbolines under metal-free conditions

An I2O5-promoted three-component tandem reaction for the rapid construction of alpha-carbolines has been described. The present approach starts from easily available starting materials, chemoselectively producing various alpha-carbolines in satisfactory yields under simple and metal-free conditions. Most importantly, this strategy can provide anticancer active molecules in one step on the gram scale. An I2O5-promoted chemoselective three-component tandem reaction of indole-3-carboxaldehydes, ammonium acetate, and alkynes for the construction of alpha-carbolines under metal-free conditions has been described.