Diastereoselective Synthesis of High Functionalized 4‐Imidazolidinone‐Tetrahydro‐beta‐Carboline Hybrids via divergent post‐Ugi Transformation

An easily scalable and highly diastereoselective synthesis of challenging 1,2,5,6,11,11 b ‐hexahydro‐ 3H ‐imidazo[1′,2′:1,2]pyrido[3,4‐ b ]indol‐3‐ones is accomplished through divergent transformation of Ugi 4‐CR products. The trimethylsilyl trifluoromethanesulfonate (TMSOTf) mediated intramolecular condensation of a series of Ugi 4‐CR adducts generates a N ‐acylimidinium intermediate which undergoes ring closure to selectively afford the target title compounds in good to high yields.