Novel Borane Reduction of Ether-Protected Aromatic Lactams^†

Borane reduction of ether-protected aromatic lactams produces 1-alkyl-1,2,3,4-tetrahydroquinolines (5 and 6) in excellent yields. This reaction provides a novel one-pot tandem process for reduction of amide group and N-protected groups. Experimental results demonstrate that the reaction proceeds through two consecutive elimination and reductions via two C−O bond cleavages to form the foresaid products.