Three component tandem reactions involving protected 2-amino indoles, disubstituted propargyl alcohols, and I2/ICl: iodo-reactant controlled synthesis of dihydro-α-carbolines and α-carbolines via iodo-cyclization/iodo-cycloelimination

Two simple, highly efficient three component tandem reactions for the synthesis of diversified NaNb di-carbamate-4,9-dihydro-3-iodo-α-carbolines and Na-carbamate-3-iodo-α-carbolines have been described. The strategy involves one-pot condensation of bis-carbamate protected 2-amino indoles with disubstituted propargyl alcohols and I2/ICl. The salient feature of the reaction involves iodocyclo-elimination of Nb-linked carbamate under mild condition in the final step.